A weird situation.. need advice.

I am a step dad to an autistic son. He’s 18 now. I met his mother 11 years ago and life has been great.

He is non-verbal with ADHD. He also has OCD and is psychopathic. He is on medication to help with the ladder 2.

In the past 11 years he has been great. We have had 2 neuro-typical girls of our own (3 and 5 years old). I’ve gotten a better job to allow my wife to stay home and raise our children. Everyone got along great.

Back to my stepson. Sometimes he’d get up in the night and sneak icecream or do typical stuff like dump out all of the flower or cornstarch. He’d often make little concoctions in the sink. Nothing destructive, just messy and I guess a bit annoying, but nothing we couldn’t handle.

I’m his later years, he has been more and more aggressive. When the girls are playing and laughing, if they get too loud, he’ll often start stomping to show his frustration. I get it. Probably a sensory thing, but he weighs 260 pounds now and could be quite destructive. We will tell our girls to stop being loud, or have them play in their room instead. But recently he has skipped stomping and gone right to elbowing and punching the walls. He’s put multiple holes in the walls that we have fixed. He has destroyed cabinets and dishes. If I’m around I’ll usually say sternly to him to stop, and he does. But if it’s just my wife, she stays quiet while he paces around and hits the walls. She thinks it will continue to trigger him.

Tonight he was angry again because my daughter was in the hallway talking to her grandfather when her mother asked her to come upstairs (literally word for word from my father in law on what happened)He walked over to her and stomped on her foot. She started crying and while she was crying and pleading for him to stop, he continued to press the heel of his foot into the top of her foot. My daughter is 5 and weighs maybe 40 pounds. Super tiny. You can imagine the size of her foot.

I need to ask the men in this sub what they’d do in my situation? I wasn’t there (thankfully) and when I had heard about it, it was over an hour after it happened. My wife didn’t see it either, just my daughter and my wife’s father.

I’m at a loss for words. I kind of freaked talking to my wife. “What’s next?” I said. “What if he elbows the top of her head? It could kill her” as he sometimes elbows the tops of counters straight down on them if he’s mad.

I don’t know what to do or think. I don’t want to be on guard 24/7 in my own house. I guess I just needed to get this out and ask for advice.