Is AUTHOR wrong in the post ? POST : My parents got divorced when I was young and before my mom remarried she was abusive; verbally and physically.

When I was around ten, my mom got re-married my stepdad. Great guy— super guy; taught me everything I wanted to know about everything. He was nice, kind, patient, understanding and knew a lot about everything… No complaints.

12 years ago, my stepdad got hurt at work and became 100% disabled. The relationship between my mom (69y) and he (70y) soured; they had lots of fights. Mainly, over money. My mom was spending more money than he was getting from medical and benefits. Over the last 5 years, she threatened to divorce him many many times.

10 months ago, she did it. 

He was out in the yard. When he came back in, she was gone; no note, no nothing, just gone. That afternoon, he called me wondering if she was with me or if I've heard from her. 

The next day, she went to the bank and took out $40k and then vanished for a week. Completely off the wall… 

3wks after, my wife and son were visiting my stepdad to take him his meds, and my mom showed up. She was irate. Screaming, yelling, throwing stuff, getting in my wife's face, calling her names; all while my 12yr son watched in shock. It came to a boil when my mom seemingly charged to my wife (as to attack) and my son jumped in front of them and told my mom (his grandmother), "that's enough of that." — he's a black belt in TaeKwonDo.

Having that happen, it was a breaking point for me. I knew she could be mean and abusive and I NEVER wanted my son to see anything like that. But him to see that and have to step up like that, it cut me pretty bad. After that day, I didn't want to speak to my mom… Still very upset with her.

2 wks later, she filed a restraining order on my stepdad and had him kicked out of their house (paid for). He had done nothing wrong. I had to get off work at a moments notice and go to the house, meet the police, and then help him pack all the stuff he could in 15 minutes and get out. He was essentially homeless. He was a mental wreck. 

After 40+ years of being their stepdad and thousands of dollars of help on various life issues, my sisters would not help him at all.  Of course, I let him stay with me for 2+ weeks and helped him find an apartment.

Over the next, few months I helped my stepdad with everything I could, but my sisters never offered anything. They wouldn't even call him. And during the whole separation early on, they agreed my mom was being unreasonable.

They are now divorced. 

I don't speak to my mom and my sisters won't speak to me. I'm not mad at my sisters, they had to pick a side (I guess), but why would I be the bad guy?

AITA for standing by the man who taught me everything about being a nice person, and not speaking to my mom because of her abhorrent behavior in front of my son?

&amp;#x200B;