If a gambler comes to you for money and you have the money that you wish to give, you should give them but never expect them to return it. If they return it that fine and if they don't that's still fine because you have already made your mind from beginning that you aren't expecting the money from them. That's the only way you can be free from any friend that is a gambling addict.
Only someone who's extremely rich can do something like that because when someone gives money to someone then that person expects to get his/her money back. In case if someone makes his/her mind to donate some money to a gambler then that would work but in most other cases something like that never happens.
Even when it comes to money, you and I both will think twice or many times before lending some money to a gambler whom we know would not return the money that we lend. Lenders are there to earn interest and that's the reason behind lending them money. If lender doesn't get their money back and or interest then why would they even lend someone money.
I don't get the idea why anyone should finance gambling for someone else, what is the point in doing that? If someone is rich, there is a ton of good causes that someone could help realize, but definitely not to give random people cash for gambling.
you should give them but never expect them to return it
I doubt that someone "should give them" as there is absolutely no good reason to do that and if it is known that someone is addicted, it would be irresponsible to consider giving money for gambling at all.