Stars $22R: Is this guy a genius or a donk?

[Bolero]

Played my first rebuy on PokerStars, so admittedly not versed in rebuy strategy. Ran into a guy who re-bought five times before the break. This guy was re-raising all-in pre-flop from middle position with an unbelievable range of hands: A-5, K-8, Q-9....hands I normally pitch to an early PF raiser. He eventually took me out.

I checked him out after the tourney, and he has made some huge scores for hundreds of thousands of dollars. So maybe I am missing something here. He's obviously doing something right.

Is it sound strategy to gamble/rebuy/gamble/rebuy in the hopes of massing a huge amount of chips on Stars? My instinct tells me that this is not a profitable approach, but, again, I don't have rebuy experience....nor do I have hundreds of thousands in winnings, as this guy did.