My dog rushed/tried to bite me, three times today. Could it be my scent, my grandma or Am I just bugging him?

My dog has rushed me, three times today.

First & second time, I tried to rub poop off from his left cheek with a green cloth. Thankfully, He ended up getting the cloth and not my fingers. I gave him, a rest for the day by not going to check on him. I did call out to him, a few times, during the timing where I wasn't checking him.

The third time was later in the evening when he was sitting/laying sort of and I usually rub the middle of his head when He is in that position. I placed my fingers in the middle of his head to massage that area gently. Thankfully, I had placed my hand abit far from him as I had a feeling He was going to repeat his actions. He did raft me and dragged his teeth onto my thumb finger. In the past, He was fine with me doing so.

Lately, I have been helping care for grandma. He absolutely dislikes my grandma. I help to hold her to get her to the chair, bed, bathroom. I use to sleep with my grandma to help her incase of anything happening at night. Since last week Wednesday, I stopped sleeping with my grandma as my aunt decided to sleep with her. Last night, I had to sleep with her as my aunt was out late. Today, He rafted/rush/tried to bite me, three times.

Could it be her scent? Could it be my scent? Could it be that he misses my dad. He has bite me in the past and other times luckily, I was able to move my hand away..

He absolutely loves my dad. My dad would usually take care of him but He hasn't done so for the entire of December. My dad isn't well so He isn't able to be around him much like He used to.