There are several ways in which gamblers can be assisted out of their addictive condition but the first step into achieving that is when the gambler accepts their condition and is ready to make mends to their problems. This is when you can help them out through your ways or strategies.
Yes, the fact that a gambler can not admit it when they are going wrong in their lifestyle, that means they don't actually need help. Only offer help when they need it and if maybe you try to help someone that is addicted and he rejects it, then don't worry yourself.