Is there even anything you can do with her once you get her to your house, besides the blowjob? Feeding her seems to bug out for me sometimes (it won't let me stop), and trying to rehabilitate her doesn't seem to do anything yet.
What do you mean by "won't let you stop"? AFAIK it's not bugged but it just becomes repeatable after you pick that option the first time. How you treat Fairy in the dungeon determines whether you set her on a path of healing, or keeping her damaged.
The three "Healing" options (talk to her, feed her, give her what she wants) must each be done at least once to complete the quest, which permanently sets her on the path of healing. After that, the "Feed her" and "Give her what she wants" become repeatable with no affect on your relationship with Fairy.