I've seen many use site blocker so they could stay away from gambling even when impulse hits. So yes, changing your environment is key, but pairing that with therapy and community gives the best shot at lasting recovery.
Therapy is the best treatment a family is to give a suffering person, brothers and sisters are the most effective therapist for such players. But rarely have I seen an addict so lucky that he gets to mix up himself in an environment where his family takes the therapy work upon themselves.
Problem gamblers face - from family multiple shame and insults instead, and thinks endlessly of the words said to them for just the issues they're undergoing. Which worsens the situation. In cases where the environment is of gamers, it's also great that the player leaves to a much quiet neighborhood where he'd have no authority to wager money.