feral cat relocation question

I had 3 feral cats, all siblings, all 5 yrs old, all with microchips
Had them for 5 years living in a wooded area behind my apartment.
Fed, vaccinated and "fixed" them all.

1 yr ago I moved to a home that had a very large preserve in the yard.
1 of the 3 cats left the 1st day - never came back.

Today I was contacted (via the microchip #) by a guy 3/4 mile away in my
complex who has been feeding her for 9 mos and wanted to adopt her. He has
an indoor cat and thinks she is friendly enough to adopt to being an indoor
cat too, although he has never had her inside his home yet (back patio
only).

I would like what is best for the cat, and IMO, that is to live in my yard
as an outdoor cat with the 2 siblings.
But....I would like to know if I take her back WHAT IS THE BEST WAY TO
ENSURE SHE KNOWS THIS IS HER HOME AND DOESN'T RUN AWAY??

Or should I let the guy keep the cat, although she is a feral cat and not a
housecat, and I don't believe integrating her with his housecat will work?

Advice...

Bob in south florida