HI.
I was going to suggest night terrors. My DD1 used to have them.
She'd wake up screaming through the night & was really worked up, but I couldn't touch her. If I tried to comfort her she'd freak out even more. She was about 16 months old when they started.
Eventully she'd settle down & I could pick her up & cuddle her, but I'd have to wait til she calmed down first. I'd sing to her, or just talk to her. If I could I'd put a hand on her leg or arm.
She grew out of it though.
She still talks in her sleep, & occasionally sleep walks, but the night terrors stopped after a few months.
DD2 never had them, Don't know if DS will or not.
No idea what causes them, or why sometimes they can't be comforted, but it will stop.
It might go on for a couple months, but I know for sure that DD1 was over them by the time she was 2.
Good luck. Hope it settles down soon.