I think you two are right. I will just stop keeping cash in my purse. This will mean that I will also have to hide the credit and debit cards because he has taken them in the past, so I have no reason to believe he wouldn't do it again.
There have been days when there was no bread to make sandwiches for him to pack his lunch. I gave him money. He skipped lunch and brought home beer. I need to make sure there is always food for him to take so that he can't use that as an excuse either.
You're right about saving the money and what I could possibly have to use it for in the future. Good idea.