Sleeping

Hi, I have just joined.  My 23 year old son has recently been diagnosed with ASD and traits of ADD. He is very isolated since covid, due to uni being online and is on the computer all the time. He has gotten into a sleep pattern where he can't fall asleep til 4,5 or 6am in the morning. Partly through years of habit, I think, but wondered if the ADD is not helping. He is trying the light therapy lamp, herbal tablets and mediation and is going to bed at normal times but lies there for hours. I've looked that info on here and will be trying Sleep Scotland. Is also going through transition from male to female soon and is facing so may challenges. Is this something anyone has experience of?