My 18 Yo Son Has Orthostatic Syncopy That He Can't

My 18 yo son has orthostatic syncopy that he can't get off the floor with. His hands are strong but his head feels weird. He is writhing on the floor but can't stand up. He says he feels like his body is shutting down. He has an antianxiety to sleep with. This has been going on for 4 years and we've seen numerous Drs.