1/3 players are terrible for the most part. $15 raise is standard now from any position.
it would be nice if you had a read on villain as to what he likes to open with but my guess is he is trying to get value from a decent starting hand. AK, AQ, AA, KK, QQ but then throw in an pocket pair.
when you raise the flop, make it bigger, with two players still to act behind you. you want to get heads up with the original raiser.
when the ace hits the turn, this is your money card, any Ax is never folding.
bet 40% pot on turn and shove the river, especially if no flush comes, makes him think you missed the flush and are trying to buy it