Seller financing with the seller renting the place

[Tom Sharkey]

My father has a life-long family friend who has recently retired with his labor pension. He's in in late 60s and he lives in a house in a very hot area. It's completed paid off as he bought it for like $8k back in the day. The place needs quite a bit of TLC but he's happy to live in it. I'd like to start a conversation with him about seller financing the house to me but allowing him to be my renter if he desires.

Has anyone done this? How do you explain it to them gently as to not scared them off or have the conversation shut down? What does renting to a seller look like when it come to money transaction?