So what drills would you use for training for bear defense? Let's assume a scenario similar to the one the guy encountered.

Is it "reasonable" to practice those drills? Well, some people train self-defensive pistols techniques that assume you've been shot in one arm and your gun has malfunctioned. You need to transfer the gun to the hand that still works, clear the gun one-handed, etc. Now add some moving targets (assumed to be armed), some moving "no shoot" targets, low light, etc.