Without knowing a lot of information, I would suggest that the pilot was trying to fly a too small, ground referenced pattern with a crosswind that was a tailwind on base leg. As the pilot banked to reach the runway centerline, the airspeed was insufficient to maintain "level" flight. Guessing (again), most pilots try to rudder around the base to final portion of the pattern if they are over shooting the runway centerline. A spin is a result of uncoordinated, stalled flight. The fact that he recovered from 2 previous stalls is actually pretty amazing. This, by the way, is the #1 cause of aircraft fatalities.

What could have prevented this accident?

Would an AOA device have prevented this accident?