It’s now common to see people get into betting addiction, there is no difference in his type of addiction to others hence, seeking professional help like a therapist is likely the quickest solution to get your friend out of the addiction.

Natural solution is to get him to accept his responsibility or accept the fact that his an addict and from that solutions could be opened up, as not speaking out the root cause to his addiction could be the reason why his not stoping, once he is able to communicate so level of information you could actually talk him out of it.