That's why it is very important for addicted people to keep them busy in some other activities to stop thinking about gambling.
There is actually some rehab that rehabiliate those who are addicted to it so you could always choose to do it yourself or to put him in some rehab though that wouldnt matter at all because to cure addiction of gambling, someone needs to suffer first and wake up from their dream. By suffering, I actually mean to lose ton of money from gambling
I've been trying to quit poker for quite some time now... I almost never deposit anything, I just play good freerolls and then grind up a big bankroll but then blow it playing too high stakes. Its not the money that im losing but I just feel really sad after playing for 20 hours then going broke.
However I think occasional social gambling is fine, since it can be a lot of fun whether you lose or win. Social, because usually good friends will force you to stop if you start tilting and betting more than you can actually afford.