CZ 75- Probably best fits all of your criteria, although a brand new model is likely to eclipse that $500 mark. But you can come close. There are also many clones of this gun that can be had at very good prices. The EAA Witness
is one of the better CZ clones you'll see, and they are available at your price point. And if he was determined to stay under $500, the Witness is exactly where I would begin my research.
BHP clones- (FM Argentine, Arcus, etc)...good $300-500 guns.
Sig P226- Excellent used can be found around $600.
Beretta 92- It's a bit of a polarizing gun, because it's massively overbuilt...in other words, it's just way bulkier than it needs to be. But it's a good gun, and that extra material can be beneficial to shooters with larger hands.
My CZ 75b and BHP. Probably have $1000 (total) into the pair: