What’s the simplest and safest way for Frankie MacDonald to store his BTC?

1) He only responds when he’s interested

2) He is using an old Well Wallet (formerly Rise Wallet) that’s been depreciated and I haven’t been able to convince him to move to a new wallet yet.

3) I tried to get him on lightning & nostr and he didn’t engage. Maybe too complicated.

4) He knows not to give anyone his seed phrase nor tell anyone how much BTC he has.