fold preflop, fold flop, fold turn . . . the pot is pretty small.

Preflop, I don't know what other people think, but this hand is to crappy to try to ISO with.

On the flop, even if he has what you think he has the RIO merits a fold. Calling against a PP 66,55,44,22 gives you break even odds. You're losing money to all other PP. His flush draw has 15 outs against you. Pretty much textbook RIO.

As far as the river goes . . . what are you getting value from if you do raise? You beat A6-2. I'd bet an ace, and I'd call an ace, but I wouldn't raise an ace.