Well serves him right for raising 4 times in a row. It seems like you got all uppity preflop after seeing him do this, and then got lucky catching a piece of the flop. He got all uppity because you raised him back and thought that maybe his ace was still good.

He too had a lot of balls to continue with he hand the way he he did, and A5 is still a good raising hand against a random BB. But giving his willingness to give action, I wouldn't play that kind of trash preflop against him again.