Sister in law throwing out 13y nephew help -Michigan

So my sister in law has 2 children with her deceased ex and one child with the new hubby. This is only mentioned and important because the 2 children are treated astronomically different from the youngest child (who is her current husband's spawn)

This is an overly religious household with very strict rules and consequences. The oldest is about to graduate and has turned 18 and has wanted out but her mom is making life a living hell at school so she's staying til graduation then getting out and cutting ties if necessary. The drama and fighting has spilled over to the 13 year old boy. He's constantly in trouble in their home (for things we would never punish our kids for mind you). He's been in trouble a handful of times for typical "boys will be boys" behavior (being in the park past closed, riding bikes on the beach where restricted, nothing serious)

Multiple times I have received phone calls screaming at me to "come pick up my nephew because he's no longer welcome in my home". The kid is obviously distraught each time. He usually only misses one or two days of school spends the weekend and is back at home after the weekend. We get a call like this once a month. This past January they didn't call me and just took his phone and kicked him out. His 17 year old sister called me crying because she didn't know what to do and they would onky let him take the cloths on his back and his school bag. Everything else "they bought him and he had no right to it". Luckily I was able to hunt down some of hus close friends and they helped me track him down.

My ask....what can I do for this kid? No 13 year old should have to worry about whether or not he's gonna have a place to live the next time his mom is in a mood. I can't just pick him up and have him live with me, that's kidnapping. I'm worried that next time they kick him out and find out I'm helping him I could get in trouble, or be issued a no contact since there's no recorded prior incidents at their home.