let him starve.

just buy a bunch of small locks and put them on the neutral tine (that's the one with the hole in it( in the US though)) on the cords to his electronics much better that taking them away he gets to see them but not be able to use them }:->

Fake an episode and pretend he's Taliban you have to "interrogate" and scare the shit out of that little bastard.

First thank you for your service. Second when he is out of the house change the electrical breaker or fuse for his room so that it trips whenever he turns that stereo on. Or short sheet his bed. Or replace all of his underpants with thongs. Or cut one of his bed legs shorter than the others. Or super glue the door handle of his room. Or get a service dog that protects you. There are so many ways to get even. However God bless you.

Your step son is an asshole.

I agree get noise cancel headphones and blast taps

I would suggest taking everything that had ANYTHING to do with the sounds that he played. That would mean speakers, cell phone, and likely internet access. Might as well take his bedroom door while you're at it. Hold it all until he can prove to you that he has learned the lesson. Have a serious talk with his mother as well. Intentionally triggering a serviceman's PTSD is NOT okay, under ANY circumstances.

I can strongly sense this is the work of a white child

That little bastard needs his ass beat. And maybe he should be thrown into the military and sent on tour so he knows what it's like. OMG if that had been my kid, he wouldn't be able to sit down for a week.

Thank you for your service and you certainly didn't deserve that. I hope your wife had a talk with him, I know I would have.