Gambler who addicted can encourage, but need a people/person who oversee, at once become a tutor, means a people/person who can control such a gambler who addicted to follow the instructions or even force him/her(gambler who addicted).
I think the activity is not just sports, it can be anything which he/she likes and can distract from gambling activity, make him/her stay away from any gambling equipment and even erase he/she gambling account.
(The grammar though)
I think you are starting a world war 3 here , erasing someone's gambling account is not really necessary to help them to quit gambling, it will just cause a fight between you two or worst, because if you really want to help them, you will do it in a better way, like encouraging him to do something that is worth of his time than gambling. For example is this forum, teach him to do signature campaign so he can earn bitcoin per week, and not to lose bitcoin everyday, and I think that is great.
To be honest, we can't really change someone by just saying good things to them, encouraging them to do good stuffs and quit the thing that they do that don't benefits them, because if they do really want to change, it must be from their heart, they must be dedicated, so that the "Change" that they are looking for can be achieve by them.