I didn’t read all the pp so maybe this was mentioned. Does he have a wrist watch? You could get him even a cheap one and set a morning alarm for him. I’d do that in addition to other bedroom alarms.
Otherwise, is there any way you or Dh can open his door A half hour before class and say, “hey, get up!” And then have a written out list of what he needs to have done before class starts. Or maybe a chart where he gets a star for days without incident and at after 21 or 31 stars he gets a really big LEGO set or nerf gun, etc. Those kinds of charts worked REALLY well with my kids.
" I object to violence because when it appears to do good, the good is only temporary; the evil it does is permanent." Mahatma Gandhi
"This is the ultimate weakness of violence: It multiplies evil and violence in the universe. It doesn't solve any problems." Martin Luther King, Jr.