It is insomnia. I think he might be going through something. Might be a big thing or something that's apparently small that's slowly having a big effect on him. I've been having the same issue for almost half a year now. Within a span of three months at the beginning of the year, for tragedies happened in my life....one after the other. Before I knew it, I was staying up all night on my computer because even when I got into bed, all I'd do was toss and turn till around 5 or 6AM or cry for hours till my sheets were wet and my head hurt like crazy. Eventually I had to get sleeping meds but I was warned that it could get addictive so for the first three nights, I took 1 tablet, as described, then the night after, I took half a tablet, then 1tablet the next night, then half, then skipped, then half....Basically cut the dosage to a bare minimum. The thing is that the meds are so powerful that I could sleep for twelve hours straight and still not want to get up but with half a tablet, I still get knocked out, even if it's just for 5 or 6 hours, it's a lot better than how it was before the meds. I still sleep really late but it's not as bad as it was before. Anyway, my point is that I struggle with sleep because my anxieties eat away at me without me even trying. All the times in my life that I had this problem, I was going through something tough. The last time it happened, years ago, I would sleep for literally 3 hours a day and I was stretched pretty thin. Sometimes I really wasn't sure at all if some of the things in my mind were actual memories or dreams. Try to watch him closely for a while (without being obvious, of course) and find out if there's something going on with him that he isn't telling you. Maybe fixing that will fix this. Otherwise...It's a tough one TBH, mostly because he's so hesitant to your suggestions...You might have to seek professional advice offline. Not sure if that was any help...