Prop Bet

I have been offered this prop bet. Both players will be playing heads up NL Hold'em, starting with 3K in chips and blids starting at 50-100 and increasing every 10 min. My opponent will be playing with his cards face up, and be moving all-in every hand. If he wins he gets 4:1, if I win I get 1:1. Who has the advantage in this bet, assuming, I only decide to call him when I am at least a 70% favorite