(((Burnsie)))
It's SO hard for us to say, "You're on your own"
But, it's something that needs to be said. You are sharing rides, hopping rides to get groceries...YOU are being taken advantage of, and since you're so easy, he'll do it over and over.
We also were doing that check cashing thing, we just recently, in the last year said, No more, because we're on a limited income, and we shouldn't be doing that anyway.
I sure can understand your wanting to "help" him, but he NEEDS to be independent, and responsible for his own behavior.
Start living YOUR life, and let him live his.
I know it's difficult to do, but it does get easier with practice.