I don't like being misunderstood either! I don't think you are "keeping him" from getting an independent life, I understand that he is hanging on and won't leave peacefully, and that is horrible to enforce. I hope with everything I have that I never have to deal with the issues that an Alcoholic husband brought in a child of mine. I beleive it is different and more difficult to navigate when they are your children. I also beleive it is more difficult when the addicted/alcoholic family member is your parent, because your world view is defined by that dysfunction.
Of course we have hopes and dreams for our children, that they will be happy, live lives that they define as meaningful, that they continue to grow and love and prosper. We would be odd parents if we didn't want that for those that we brought into the world. And of course we want to help them through rough patches, and smooth their road if we can.
I also understand that you are very sad and worried for him too, which is entirely natural. I have no doubt that all your actions and feelings are borne out of love for your son.
he is chosing not to take responsibility for his life, I don't think that is your fault, in any way. If my mother asked me to leave I would go, quickly, quietly and trying to make amends for any behaviour that had precipitated that. You have given and put up with more than most parents would. He isn't grateful for your help, he wants far more. I don't think your son is bad, but he is playing on your feelings of guilt, probably unconciously.
You mentioned having alcoholic parents? Most of us vow never to repeat our parents mistakes, when we have children, I wonder if the guilt, the feeling that you are abandoning someone who has no-one else (because no-one else will put up with him) has anything to do with not wanting to repeat their parenting actions toward you. May be entirely off base.
I'm glad you are here, I'm sorry if anything I wrote came accross as critisising you. that was not my intention. (())