You're had a rough life and to have gotten this far you must have some significant internal strength. However I think your efforts at improvement (of this boy's life, at providing shelter to his hapless mother) are misplaced. The happy life you want is within your reach--but only if you put your considerable strength at finding what brings you comfort and joy. At the earliest opportunity, I would evict this young woman and her seriously ill son from your home. Before you cry that you love her--you can still love this woman when she finds another place to live. It is entirely possible to love people without enabling them. You are still young (oh, I know you might not think so--but yes you are) and there are loads of nice honest people out there. I suggest you find yourself a therapist and begin building the live you truly want without these horrible and potentially dangerous compromises.