[Obscurity4340]

Do all that but have you considered good blinds and maybe even a sleeping mask? I'm on your side but good tools to have for anyone, particularly with or without such a condition. The sleeping mask Tim Ferriss recommends is amazing, I hate sleeping without it

[Obscurity4340]

Also make sure he makes his phone/screen orange-tinted at night and let him pick out an album or book he loves and teach him to listen to it every night. Slow down the speed as far as he'll tolerate and set a sleep-timer for like 1.5h to fade it out. Also, turn down the volume just so he can barely hear it and has to strain a bit to hear it.