You could suggest (if you're that close) he try some of the standard remedies for serial snorers/sleep apnea sufferers - lose weight, firm mattress and lay off the alcohol. That might improve his night sleeping thus having a knock-on effect.
A while ago I worked in a distant association with a bloke who was fairly trim, used to sleeping on very thin (1/2") mattresses and rarely drank alcohol but suffered from sleep apnoea so serious he was unable to work for about six months; we lost touch while he was away but I gather the full might of the medical profession was of very limited use.
In a previous life he had been a high altitude guide in the Himalayas and I forget how many times he'd been on and up Everest and we wondered whether this may have been a contributing factor.
But I can't offer anything more constructive in your situation, Wesley.