I think you are describing detachment, which is healthy. As for not feeling "more", there comes a point with a parent who is mentally ill or a substance abuser (or both, in this case) choosing not to get help where you simply stop taking it personally. We are conditioned by society to love and respect our parents so that guilt is an outside factor that has no place in our emotions. Don't take on that baggage just because you think you should be feeling a certain way. Feelings are feelings, they are not right or wrong.