MIL won’t stop buying scammers gift cards

My MIL was involved with a romance scammer last year. We got her away from that but now she’s addicted to gift card scammers. She thinks she’s getting a Tesla, she thinks Tom Selleck is her bestie, etc., and they all need gift cards from her.

Has anyone successfully stopped someone from doing this? We’re trying to tie up as much of her money as we can, but she won’t stop and is now searching her house for loose change to go buy more. She overdrew her account, has asked friends to help her get gift cards, and is destroying her life and relationships over this. As soon as she gets her next SS check it’s going to get spent on gift cards.

We’re now considering buying her an iPhone and installing apps that are supposed to block everything. Currently she has an android and it offers little in the way of solid parental controls.

TIA for any advice.