Your initial recommendations were great. My suggestions in order of preference and depending on if he is willing to dress around his gun or not:
G19 or G43
M&P9 or Shield
[Long gap]
Whatever current manufacture Ruger/Springfield/FN/HK/CZ/Walther/SIG.
They'll all be okay with their own drawbacks. Most will be pretty reliable and pretty accurate and within his price range, but as his first (and currently only) handgun I'd want to see him go with something quality that has a good chance of being supported with holsters, sights, magazines, spare parts, duplicate guns, etc for the foreseeable future. Nothing else competes with Glock or S&W (in that order) when it comes to US handgun adoption and aftermarket support. The import/manufacture numbers available from the ATF show that very, very clearly.
Considering semi-auto pistols only in 2016:
Glock manufactured 368,140 handguns in the US and imported another ~1.2 or 1.3 million from Austria.
S&W manufactured 1,429,451 in 2016 with a big chunk of those M&P series and Shields.
Ruger built 1,010,236 but most of those were .22s.
Sig Sauer USA built 580,588 pistols
Springfield manufactured 72,013 and imported about half a million XD models.
All the German companies combined (HK, Walther, J. G. Anschütz, etc) imported about half a million and had minimal US manufacturing.
CZ-USA built 9,787 and imported approximately a hundred thousand.
FN imported about 25,000
As you've discovered for yourself, even "big name" manufacturers like SIG will sometimes arbitrarily drop all factory support for a gun without warning. I don't see that happening anytime soon with the G19 or M&P9.
All of the above assumes he's a shooter, not just a gun owner. If he is a non-shooting gun owner then it literally doesn't matter. He can buy a gun, maybe an extra magazine or two if it doesn't already have one and some sort of holster. Add a couple boxes of ammo and he'll be set for the next few years ... if not for life. With most gun owners, they'll never have to replace the sights, never need to buy another magazine, never break a part on their gun, almost never carry so they won't really care if their holster works well. For those folks, it doesn't matter how snowflake unicorn their gun is because they don't use it enough to matter. The up side to never using them is that they get to repeat over and over that it "never jams" and "never breaks".
