I would suggest that both you and your mother get to Naranon meetings and read Codependent No More.
Enabling is not the answer, in fact it is part of the problem. Until she falls to her knees she will never have a chance to get back up and find recovery...for life. She is 24, should have a job and a place of her own to live, not living with you or your mother.
You can't change your mother or her thinking, however, you can change yours, allow your daughter the diginity to find her way, hopefully to recovery, so that she can become a responsible, productive member of society.
Sending support your way.