Definiately budget for some fun otherwise its like a punishment.
Some easy things: Pack lunches don't buy, when I first started doing this I had to put my car keys in the fridge with my lunch the night before so I wouldn't forget it, now I dont forget and feel guilty if I eat out.
Receipt envelope, he should get a receipt for everything he buys and stick in the envelope, every weekend log it in a spreadsheet to see where he is spending his money and what can be cut out. When I did this I was shocked at the little things and how they added up, those ATM withdraws and checks for cash wont tell him where his money is, only the receipts will.
Check with your city or county government, there are many who offer free classes on budgeting and such.
Some fun and inexpensive things to do:
Instead of spending $30 for a movie, rent a movie or better yet borrow one from a friend, pop some popcorn, light some candles, grab a blanket and stay home, much more fun hehehehe
My college age son told me that game night has become huge on their campus since none of the kids have money, they get together and play different board games together at least once a week.. He is in a apartment but he said that this is all the rage now in dorms as well, often several different games going at one time on a floor. Maybe you can do the same, invite friends over, make homemade pizza (about $5 and FUN to do).
If he is into buying magazines, books and newspapers instead of buying read them online, much cheaper if not free.
Head to a park, the mountains, etc on the weekends, bring a picnic, invite some friends or go alone, usually free except for gas.
Find new and inexpensive things to do - If you have a digital camera start learning photography, lots of free lessons on the web, head to a park or a local rec center, often there are pick up games going on, pick out an inexpensive recipe from a cookbook and teach yourselves to cook new and interesting meals.
Most importantly, hold him accountable but at the same time you can't "nag" him, as an X-bad budgeter I can tell you that constant talk about it was not a good things, when we switched to a weekly review, I got it easier, and there was less stress, now my budget is a game.
Good luck to him!!!
Kelly