If you are 34 why did you need someone else to be a payee to begin with? Did something happen that you were declared unable to care for the majority of your money?

If your mother is not using the money on herself (and with your father that wealthy I do not imagine that she is) perhaps she's trying to show you how to manage your money. Your parents won't be around forever and I'm sure that she'd like to know you'll be ok when they are gone.

Was your mother aware that you were struggling with having enough money to buy food?