Especially, with the current situation that makes people stay at home, I suspect those can play slots all day. Their family will have a big role to cure their addiction, so I think you need to talk to their family. You also can advise them to limit their time in playing and remind them about the bad impacts of addiction. If they are not too addicted to slots, I am sure they can change their habits gradually after hearing suggestions. But if it doesn't work, they need specialists or experts to cure them.
I know that gambling is an absolute decision for anyone whether they agree or not, but if there are no rules about age limit for the players, it looks like mass addiction will get out of control. I could hardly believe at first people would be so addicted to that slot game, but now the reality is it's true. I always tell some friends that if they like to gamble then they should be a responsible gambler so that they can minimize any problem that occur after losing.