He should seek out professional instruction in several areas: 1) unarmed fighting, 2) knife fighting, and 3) gun fighting.
Some example course tracks:
1) Unarmed: attend several self-defense seminars. Unfortunately, unarmed fighting is difficult and takes time to learn well. Therefore, the idea here is to get good at a few moves. Take a look at "Inside the Crucible" by Kelly McCan and "Die Less Often" by Suarez and Denny for some examples. He may want to talk to Marc Denny at Dog Brothers Martial arts, who is based in LA.
2) Knifing. A two day seminar and some consistent practice will improve a gunman's chances against a knife. Take a look at Tom Sotis AMOK! courses for examples. Unfortunately, many gun people hold the knife in contempt. Just as unfortunate; knives are very commonly used by thugs on the street. He really should know what to do and not try to solve it with a gun unless there is enough distance.
3) Gun: 1) NRA Home Firearm Safety, 2) NRA Basic Pistol to start. These are not great courses, but they serve as a (too gentle) introduction. I don't like them, but they fill their niche. Next, look at the fpftraining.com's Defensive Handgun Skills 1 and 2 courses. He can look around his area for courses that have similar content.
Alternatively, he could take private lessons from his local range.
He should keep it basic and try to avoid getting sucked up into terminal-gadget-itis. It'd be far better if he acquired a NOK knife trainer, some pads, a single handgun of his choice (9mm/38 SPL or more powerful), lots of ammo, and the courses mentioned above.
