These might not be the best solutions but they might work:
First you should get him to see a doctor and specify exactly what mental condition he has. Although, after reading your enquiry I do think what he is referring to is game addiction. When you're addicted to a game there is a tiny voice in your head telling you to go back to gaming, and it's hard to ignore.
Second depends on his mental condition , if it is a game addiction, you should start doing small things to sway him from gaming, like not making food for him, not cleaning the area he's playing his games in because then he can't ignore his other psychological needs. This might cause an argument but that's what is needed, make him hear u out in that argument and instead make it into a conversation.
A distraction? Probably go on a holiday?
Disclaimer I am not a professional these are just things I'd consider doing.