Hah! I have a mild case myself, but I got the dentist to make me a mouthpiece that I wear when I sleep. I haven't actually done a test to see if it really helps, but my wife tells me I don't snore as violently, so I think it's working. (There was just no way I was going to sleep the rest of my life wearing a CPAP mask.)
I find that sometimes I take the mouthpiece out of my mouth in my sleep, too. But nothing bad happens.
This may be dangerous advice, so for what it's worth... How bad is his case? If not too severe, what happens if he just goes without the machine while camping? My snoring and apnea occurs while I am on my back, so if he's like me, maybe he can work at staying on one side.