Holding and disbursing money usually works as well as holding and disbursing pills.
If you wanted to empower him, an option would be to sit down with him and teach him how to budget his finances. Help him make a spread sheet or just do it on a calendar. If he is trying to save money, he could look into a short-term CD (1-3 months) with a low minimum deposit where he would pay a penalty if he wanted to access it before it matures. Or he could keep it in there and earn some interest. If he wanted to go on a mission, he would have to do it during bankers hours.
If you decide to be the money-man, I would go to Staples and get a receipt book. Whenever he gives you money or gets money back from you, you BOTH sign on the dotted line.