By "sip 'n' puff," we mean a 15mm plastic mouthpiece, kind of like the last piece on a diving mask, that attaches to the hose, where he could take a breath whenever needed but has nothing on his head full time. It is somewhat more tiring to use so it might not be the best thing all day, but you can do some of each.
Using velcro, zip ties, bungees, etc. you can mount the hose where it's easiest to reach.
There are straight and angled mouthpieces -- I'd try one of each. They're cheap.
As for a mask, look at cpap.com; there are more minimalist nasal masks than there used to be and many have free return insurance.