i think he will turn good..but like snape.....
Also I think that Snape may play a key part in changing his mind.......maybe if he found out how snape was...OR i think he might find something out about his dad that he dissaproves of.
OR if their house is ever investigated (the basement) for dark magic items then I believe that would change his attitude too. i dont think he really KNOWS what his dad does.