A leash and harness maybe.

Of course - if she and her hubby spoil him rotten (I know you did too!), they just might make indoors a good place to be. Maybe they have a spare room they can make HIS - with cat tower and all sorts of neat things. And without teens running in and out, there's less risk of his escaping.

Maybe a kitty door with a large outdoor enclosure...that might work best.

I am glad she seems to know about the dangers of an outdoor cat.

Hey - if Potter would be really happy there, go for it!

(and visit and send pics! )