I've dealt with the same kind of family situation. Many people find it very easy to simply walk by faith instead of walk by love (they find it "convenient", but faith should be borne out of love) and are satisfied to find as many "commands" in the bible to use for the sake of persecution and martyrdom (self-glorification) and somehow believe that love can be "commanded" instead of being only FREELY GIVEN. It is the natural tendency (human nature) of many people to resent being told to "practice goodness and hospitality" that makes us feel that we must be constantly COMMANDED instead of being concerned with what God WANTS. God would rather our heart and mind be at peace instead of holding a grudge and continuously resent the person who wronged us and caused us to suffer consequences (because we are VICTIMS), but God is not or ever has been a VICTIM that suffers CONSEQUENCES. He sent His Son only to satisfy the REQUIREMENTS that are necessary for us to enter His place of rest (return to Him). So, it should always be recognized that forgiveness applies differently to us forgiving each other. Whether you rather regard as a "command" or a "priveledge" and WISE thing to do is of interest to The Lord. The Lord did not forgive us out of "RESENTMENT" ("emotions" simply are IRRELEVANT to Him), it is WE who have a need to overcome RESENTMENT.
I have also dealt with the kind of family situation you mention. It must not be left alone and ignored because, left alone, things only get worse, not better. It is SERIOUS. Read my last few posts on the Narcissist forum. The more you know how to recognize their tactics, the more you can prevent the deterioration of a family.