My other thought, if he is just going to have one pistol for a while, it will be doing double duty as carry and home defense, etc. The basic double stack carry guns would seem to be a good choice. However, what he is most comfortable and confident with is the most important part. He has his whole life to try other guns, experiment, and build up his own collection.
For that matter, for the money he is talking about, one of the 3" or 4" barreled, 7 shot S&W 357 magnum revolvers would be good. I have the 3" barreled, 7-shot S&W and it is handy shooter that isn't too awful big. Ruger has that 5 shot 44 special revolver also.