I apologize in advance for my post that will probably lack the compassion of my peer's.
I too am 35. I moved out of my parent's home when I was 17 because I didn't want to live under their rules. His apparent worthlessness is mostly his own fault, but the remainder of blame falls squarely on
YOU. Every dollar you give him frees up a dollar of his to buy weed. So, in actuality,
you are buying his weed. Even if you didn't give him money; by supporting him in other ways;
you are buying his weed. Think about it.
If you are serious about wanting a change; if you now realize the truth; give him 1 month and no more. Since you are somewhat responsible for his worthlessness, you might help him find the
cheapest,
smallest place in the area and pay the 1st months rent and security deposit. Make it abundantly clear that there will be no more help in the future. (If he ever calls and says he's hungry; give him a case of Ramen Noodles, but
never cash).
He then can choose to make the tiny amount of money necessary to pay the bills in the matchbox size apartment for as long as he wishes... or develop a work ethic (and the pride that comes with it) and save his money to improve his lot in life on his own. I honestly think that would be the single greatest gift you could give to him.
I remember reading somewhere that Henry Ford had failed in 3 businesses and was nearly bankrupt at age 40 when he started Ford Motor Company. It's never too late to learn. Your alternative is to continue treating him like a child until you die, secure in the knowledge that he'll be a basket case when you're gone. Why not do something proactive? He and you will both be proud of him when he becomes a useful member of the human race.
Ps. you might want to pick up a copy of "Atlas Shrugged" to help you understand the "goodness" in my advice. And, pick up a copy of "The Millionaire Next Door" for him so he can get a grip on how successful people manage money. In fact; pick up 2 copies of that one (you should read it too).