How to be more supportive? Your post is kinda confusing, you sound pissed off rather than someone who wants to be supportive. He’s booked in for a sleep study, what more is he supposed to do? Honestly it sounds like you need someone to vent to, to get this out.

Some things that might help you understand his situation:

Consider that he hasn’t had a decent sleep in maybe a decade, and it’s affecting his mood m and energy levels massively. He’s probably not too aware of that (I wasn’t aware of how much sleep apnea was affecting these things for me until I started on cpap). He probably isn’t aware how much cpap might be able to help him.

Also consider the idea of having to wear a mask to sleep for the rest of your life, especially when sleep apnea is generally perceived as a disease for fat old people (I was diagnosed mid 30s also, and I hated the idea).