OP actually there's no fix rules for gambling addicted people that could help them to become normal from there addiction. Wherever You are saying, by blocking websites or similar steps may work as little limitation but it won't stop anyone until a person has strong mind set to avoid gambling. Online is not only the place where gamblers do gambling but also they can do same thing in locally with other person or can visit casino house himself. So i think to prevent auch addiction, it is necessary to make them realise how addiction impect their lives and how dangerous it could be when you gambling irresponsibly without following rules
There is actually no fixed rules for gambling addiction decline but rather there are some written down guidelines theoretically proven to have the potentials of limiting or minimising the rate at which an individual or a gambler gambles. This act of limiting ones addiction is a personal decision. If a gambler is prepared and have made up their mind to stop gambling, that would help the process to scale smoothly because they are ready to do it as their mind is already made up to stop gambling but it would be a gradual process which involves phases.
Most gamblers do not really take their time to read out the rules and principles of gambling before they engage with it but rather, they are only concerned with the profit they could take home and as a result of such thought, they begin to gamble excessively and irresponsible which would result to their addiction.
Stopping gambling addiction is a personal decision and if any addicted gambler is Willingly to stop gambling, it. Should be from their personal conviction so that the process would be okay without any problems.