I have the resistance bands too along with a door jamb attachment. There really isn't much you CAN'T do with them so that's always a good thing to have around. Mine allow me to attach different weight bands to the same handles to get a real burn going.
You might also suggest one of those compact door attachments to do pull ups. They can be used at different heights in the door frame to alter the amount of weight.
Remind him that during basic, they didn't have any magic machines to whip the recruits into shape. Just the basics of push ups, sit ups, jumping jacks, pull ups, running, etc.....it ain't rocket science and I say this from experience myself...
Move more, eat less.....stay off the freaking scale and build some muscle...