In my opinion, in order to give any recommendations to a gambling addict it would not hurt to first get an education in this field, because a well-educated psychologist can really help even in the most serious situation without the use of drugs.
If I had the opportunity to help gambling addicts, I would try to completely limit any opportunities to gamble for several months, plus I would invite people who have already got rid of gambling addiction to the classes.
In my opinion this is a very good practice and it is used by some Rehabs.
We can give any recommendations to a gambling addict but that will be up to him to visit on that rehabilitation or he will refuse it because he will not accept the recommendation and will saying that he is not gets addicted to gambling. It is difficult to suggest that to that person especially if he still gets fun in gambling and can still wins some money. But we needs to reminds him to check himself in the rehabilitation and see what is the results. If he wants to go to that rehabilitation and doing the process until the result is out, he will see what is happens to him.
Maybe he will realizes that something wrong is happen to him and he will wants to cure his gambling problem with the psychologist. He needs a proof from other people who had gambling addiction so he can compare what happens to him so he can realizes the wrong thing and wants to cure his gambling problem.