AITA for not attending my parents christmas for the grandkids because my sister was bringing her AH of a husband

For context about 5 or 6 years ago my sister let's call her N(37)f now and her husband let's call him AH(36) now we're out at a sports bar one night to watch a football game with my parents, my younger sister let's call her D(33) now was watching there daughter my niece while they were out, it was pre arranged that my sister N would not drink and they would pick her up on there way home, but plans changed and N decided to drink without informing my sister D, so when time to go home N calls D and tells her she can't pick up my niece now because she decided to drink and for D to bring her to there house which is a 30 minute drive from my sister D's apartment, we'll needless to say D was not happy about this but did it anyway.

So when she got to N and AH's house D asked to speak to N privately, she agreed and in a calmly manner asked N for more than a last minute notice of changed plans or to stick to arranged plans as it's inconvenient for what she did and still has to drive a half hour home, N agreed to her terms and understood and apologized.

Then AH decides to burst through the garage door and yelling at D that next time she has an issue with N she needs to consult him first and for her not to come onto his property disrespecting him or N, I don't know what exactly what was said after that as I was not there but D along the lines told him she's not being disrespectful and he don't need to be yelling at her and goes off even more ( he's a horrible drunk) and calls D a N***** lover (yes she mostly dates African American guys) and some other names.

After a few minutes of his constant disrespect and name calling D leaves and calls me (39) f now and tells me what happened. As the big protective sister I am I call AH up and go off for how he miss treated my sister D and goes on to call me a whore and hangs up.

During all this N just allows him to say whatever he wants and does not defend her sisters. Due to all of this me and D stopped some contact with N and told our parents the situation and if AH was at any family events or outings we would not attend, I also let N know that my daughter let's call her A(16) f now would not be at her house with AH there but if she wanted outings with her AH is not to be around. As he has shown signs that I have noticed that he is a women abuser and thinks he's above us and with his current abusive outburst and signs that I've seen, ( some context to this is N works a full time job, takes care of there young daughter, does all the cooking and cleaning the house, while he just works and comes home and sits on his ass or goes out with his buddies drinking while N stays home with there daughter, but he also has a job where he gets laid off alot and during this time he just sits at home on his ass and there daughter goes to a babysitter cuz he can't take care of his own child and still goes out drinking with his buddies at night while N takes care of everything, he also argues with N on how she punishes there daughter when she miss behaves or acts out and my niece has ADHD bad but was not diagnosed at the time but she is now and he won't allow her on medication) ( I love my niece but this makes it very hard to be around her cuz of her constant outburst and doesn't stop acting out until she gets what she wants and has told me many times when I watched her one summer cuz I don't give in to miss behavior and don't give her what she wants to just shut her up like N does that she hates me) I didnt want my daughter influenced by his behavior.

Anyways fast forward a few years N finally gets smart after her and AH have a big fight to divorce him and N my niece and their 6 month old son at the time move in with my parents, during this time AH barely sees his kids, constantly rescheduling cuz he's busy going out with friends and a few times I've been over my parents house while N is on the phone with him and she has him on speaker phone so I can hear everything he's saying and even though N has betrayed me so many times my big sister protective instincts kick in and I start chiming in my peace ( as he still has not apologized for what happened a few years prior) and also during this time has called our family not just immediate family white trash, putting my parents down as they took in N and their 2 kids and helping with everything they need as he has not paid child support or hardly even seen his kids during this.

This goes on for about 2 years and then N and AH have to go to family counciling to help my niece adjust as she is a daddy's girl and AH's divorce lawyer tells AH to be nice so my sister starts getting feelings for him again and goes back to him after my parents did everything to help her and paid for her divorce lawyer and this would have been her 2nd divorce and my parents paid for her 1st one.

But anyways now that my sister is back with her AH of a husband she just expects us to forgive and forget. Sorry does not work that way, christmas last year she was smart and did not bring him around, but this year without notice she brought him to our aunts house for Thanksgiving, my parents are overlooking what he has done to keep a relationship with N and the grandkids and the rest of the family not necessarily happy about him being there deal with it for N but make no effort to actually interact with him ( luckily I was with my husband's family this year for Thanksgiving as they usually only get together for Thanksgiving once every 4 or 5 years) but my sister D was very uncomfortable with him being there and blind sighted cuz N told no one of him coming and then complained to N that he felt uncomfortable being there after they had left, likes it's my family's responsibility to make him feel comfortable after everything he has done.

Sorry so long but a lot has happened and needed to vent to somewhere other than my sister D as we feel we are right about the situation.

Again fast forward to Christmas, my parents decide to have a get together on the 15th as we always due christmas on christmas eve at my aunts house every year but my parents didn't want to bring the grandkids presents there for them to open so my mom wanted to get together before that, and when planned AH was supposed to be working but he got laid off a few days before so now he was coming.

I called my mom about some spam thing going around and wanted to inform her about it 2 days before the party and that's when she tells me that AH is now coming to the party and she knew 2 days before I called so I told her I will not be going then and N needs to stop trying to force him onto us and my mom tells me I need to just get over it so I told her I do not need to get over how he's treated me both my sisters and my family and if N doesn't stop trying to force him on us then I'm going to no contact with her ( as this was not the first betrayal from her it goes all the way back to when we were kids and I've had enough and getting to old to keep putting up with her betrayal) and she tells me that I'm wrong for that and I told my mom we'll she's wrong for what she's doing and my mom had nothing to say about that.

After I got off the phone with my mother I was P'd off for awhile and after a few hours to calm down and telling my husband that now AH is going to be at the party so we're not going I start crying cuz my mom can't even tell N not to bring AH cuz it's more important to have all her children there then just to make face for N and can't have there daughters back and D has no choice but to be there as she recently moved back in with my parents from moving back to Ohio from Texas and saving up to get her own place and I wouldn't be there for D to make it easier for her as well.

The day before I started thinking I might just go and purposely make him very uncomfortable to be there and maybe he would get the hint not to come around but the day of I started having flu symptoms and running a fever so end up not being able to go anyways. So AITA.

Somewhat of an update and to show more of how much of a worthless A****** AH is, about a week after this N broke her ankle slipping on there wet driveway after dropping my nephew and niece off at daycare while she works and he's laid off cuz again he can't take care of his own kids or even take them to daycare while he's home doing nothing, well now he has to do it all while she is laid up lol and with N's ankle now broken they weren't coming to my aunts for christmas eve, so I was told. We'll they ended up coming and I got a big surprise when I got there I saw them and as much as I wanted to go off as soon as I saw him he was not worth going through a coughing fit as I was still getting over the flu but at the end stages and kept my distance from everyone and already had to miss both my husband's family christmas party's due to me being sick I was not about to miss the last one but luckily they left early I couldn't even look at him or even talk or look at my sister for still trying to force him on us