No offense but since you brought it up...I don't know AJ's age or personality traits but I'm assuming that AJ is an adult, therefor AJ is (should be) responsible for AJ. Yes, the girlfriend sounds like she "has issues" but unless and until her issues bother AJ enough to cut her loose, she is in the house so to speak. Bottom line...AJ is an adult and needs to assume responsibility for all facets of his life.
This is just an objective observation from someone who doesn't sugarcoat. Take it for what you think it's worth. Good luck to all parties concerned