Thank you Colleen. Interventions we've tried is rubbing his back, scheduled awakenings, weighted blankets, melatonin, magnesium, lullabies (us and a sound machine), turning lights on, adjusting temperature, textures of linens and jammies, soothing voices, trying to wake him up...
It sounds like he is being tortured and he's pissed about it. He rages until he stops, often he passes gas at the end. Which we've seen GI thinking maybe it's gas related. He struggles with introception (difficulty recognizing what's happening within his body) so he's never been able to verbalize if it's pain driven, scared, dreams... and this has been continuous since infancy.

By responsive I mean that he will yell, hiss, spit, hit, kick, throw stuff at us... aimed at us. Eyes open and all. But never seems to remember any of it but says he's "scared of the night".

I just want to go in and comfort my kid but instead we've been told to "not give it any attention". So we wait it out with it being video recorded hoping it doesn't wake our daughter in the other room and scare her.