1 arm push-ups = 1.2 BW bench with extra tricep, anti-rotation work, rotator cuff and serratus work (and when he can do, say, 10 strict with feet pretty close that's about a 1.5 BW bench)
Handstand PUs = can get to a BW military (when full range) + erector work
Pistols/jumping pistols, maybe +25 lbs = ...
chins -> L-chins -> lever chins: all you'll ever need for a huge back, rear delts and steel abs
-> one arm chins: add huge biceps to the above, and insane shoulder stability
Back lever (face down) - some erector work (although he'd better do sandbag deadlifts or back extensions, they're easier to control)
...and, of course, the planche and then rainbows (planche to handstand to planche)
Practically, with a chin-up bar and a lot of will, the only other equipment he'll need to build an incredible body is a heavy (can get heavier in time) sandbag, for deadlifts and other erector work (back extensions etc.).
To be realistic, how many people can bench 1.5 bw? Or do jumping weighted pistols? Or OA Chin-ups? BW can build great strength and mass, if you have enough will. And also, how does one look when he can bench 1.5 BW and can do OA Chins? (presuming he has a high calorie diet, otherwise he'll just be very strong)
Hope this helps,
(btw, if he gets a sandbag, he can use that for lunges and squats and a bunch of other stuff; also, a sandbag can easily get to ~300 lbs - sand + water is probably the cheapest option - and it's also dirt cheap...or sand cheap) (also, fixed chin-up bars can be found all around in cities, can't they?)