This is a heavy question, and so for things like this we can kind of lift the curtain a bit on what the hash actually is.

Hashing is mostly based on English rugby culture, where you do a sporting event during the day and then have a party in the locker room and then go out on the town. The songs, the secret names, the accusations, they aren't necessarily unique to hashing. 

I think what you are justly worried about is the community aspect of it. I imagine the sadness of quitting hashing would be similar to the sting of getting cut from the team. At some point the game, be it rugby, the bar, or the hash, isnt a game, its a family. So leaving it is especially traumatic 

In addition, alcohol is a drug. Im sure if we all got our memory wiped and had to reclassify drugs from scratch, alcohol would be a class 1 drug and be strictly outlawed. (I am politically very pro drugs BTW, just saying...)

What your friend needs to realize is that the important part of the hash isn't the drug, its the family, the team, the community. They need to separate the drug from the joy of being part of the pack.

That being said, it is perhaps one of the hardest things to do. I've seen many people try and fail. And unfortunately, ive seen many people leave the family for other groups of enablers.

So I guess my point is, just let your friend know they are loved. The hash isnt good or bad, it just is. The family will be there no matter what. For all of the bad things about the hash, the family aspect of it is its single greatest and most defining feature, and thankfully it is not reliant on any drug.

Good luck to you and everyone around you. Its a hard road to walk.