There are other gambling sites that offer dice that you should try, Try it and maybe you will love some of those. Just don't get so addicted to it and you should know when to stop. Keep a limitation on your bankroll so you won't end up broke.
Finding more dice sites may just make him more addicted to it. He can play as long as he limits the time and money that he used playing. If he lose control, that is the start of him getting addicted. So for safety, I think it is best if he just sticks to one gambling site to avoid being addicted to dice games or he just quits playing at all.