Dear Cloud like~
I can see why you went to help Scheherazade, you could see the problems in boundaries, which to be honest from the outside looks like love, guilt and trying to do the right thing is overriding all - to everyone's detriment.
OK, so you have been handing over cash when asked, as many parents do, the trouble being you feel it is enabling a lifestyle that is doing your son harm.
It would be great if there was an easy alternative, that just saying 'no' would fix things and prevent that lifestyle continuing. I would imagine you are realistic enough to realize this is unlikely, and may in fact head to him seeking money in other ways. Even direct payment of rent etc only frees up more cash elsewhere.
I don't know your circumstances, however is it possible that you develop a closer relationship with your son? Perhaps he comes and helps around the house for a while each time, or you both go out and do something mutually enjoyable, then he may see you more as a freind than an source.
That could be a better base on which to curb destructive tendencies and build enthusiasm for more healthy pursuits.
As I said, I don't know you, your son or the circumstances, perhaps the above is totally unrealistic, however I'd welcome your return to talk about the matter