((((((((((paddy)))))))))))

I think you have gotten some very good advice here. Regardless, it will be hard to follow it as:
1. You share your money with your partner
2. Your partner shares the money with his mother
3. It sounds as if your partner learned money management skills from his mother and thinks his Mom's behavior is OK?

I am late to this conversation, but it sounds as if you are subsidizing both of them. In order for you to be firm with his mom, your first conversation must be with your partner.

Keep taking the Dutch lessons and put the silver in a safe deposit box! Good luck and keep us posted - we are concerned for you.