He needs to drop out of site for about a year, lose weight, gain some self defense skills, practice extensively with and get additional training for a handgun and other weapons. Its doubtful he’ll ever shoot anyone again, but he needs to stay in practice for his own safety.
As far as where to reappear, he can blend in in a number of places in central and south Texas. New Mexico and Arizona are other possibilities, but in Texas, he can carry without too much trouble.
I’m no expert on this subject, but it seems to me that “hiding in plain sight” could be much more effective than moving to a remote area. In a remote area, strangers are likely to stand out. In a large city, you can mix with crowds and live a nondescript life pretty easily.