get in the seat behind him (SB to his BB), and play agressive, show him blufffs, force him to play your game, by either forcing him to calling or betting more, and dont be afraid to fold a winning hand to his bet...make him think hes beating you

i found myself in this postion about a week ago, where a new player would either raise 1$minium preflop (.25nl) or not play at all. and he bet the pot on the flop everytime weather he hit or not, and he was killing the table.
Everybody was so on tilt, they all called with anything, and folded when he bet $5 on the flop.
The things they said to him.
I tried to slow play a set of Q's to him just becasue his big bets, the river was a 4th heart and i CR him all in and he called me with a 3s4h, and won cause i had no hearts.
Then they really started talking [censored], i told him he made a good call, and left it at that, then defended him to the others, because it was quite an amazing, total donk call...he told me i made a donkey play which i did, then admitted to not even seeing the hearts
i then rebought, watched the board more, and played alot more aggressive, getting in alomst every hand he played, after a couple slow plays, CR the river, he would fold to my CR....and i would show him the cards everytime bluffing or not....he could not read me, I lost my intial buy in only once and won about 60 from him,
then he rebought and lost another 20, i even offered some friendly advice on stuff, how to protect his hand, and some pre flop stragedy

i guess he didnt mind losing alot to a friend, and he would not attempt to push me off a hand, but he did everybody eles...lol

sometimes the best way to beat a fish, is play him as a friend, and never berate him, that hellmuth sh!t is way to overratted