"John comes back a week later and says, "Jack, I am really fucking frustrated you are still playing that shitty game. I want you to quit right this fucking moment.""
That is exactly what some people do in real life professionally in phycology, without the strong words(that denote lack of control). It works really well.
In order to illustrate this think on "Kitcken nightmares" tv program, or something like "Hermano mayor" on Spanish TV.
I use to do the same thing with friends and people that demand my help. Loner? Quite the contrary, help someone get out of a hole and he-she will be your friend forever.
I have taken people out of drugs, or gangs,prostitution this people will give their life for me. There are few things as rewarding in life(it is also a pain in the ass while you do follow the process but it is worth it).
Of course you need education in order to do that. You don't need to say you are "fucking frustrated", in fact if you are frustrated you can't help anyone.
There are masters at this, like in anything,and if you do that you will learn with every person you help. After some people you see patterns and being effective becomes easier.