I like what Yanie had to say about it. I know all about deadbeat parents, and the best thing I ever did was learn to forgive them. Now instead of getting mad at their judgment on my life, I feel sorry for them. Sometimes I even tell them that. Instead of getting mad showing someone who only knows how to be mean that they can't make you mad is actually 10 times more powerful.
When I have a family member make a negative comment about anything, I'll often say something like, It makes me sad to know that you are so unhappy that you think nothing of trying to make other people unhappy. I really do hope somehow you can find some happiness in your life so that you don't continue to try to get delight from causing others pain. There's no joy in that, and it reminds me why I choose not to spend much time around you. For your sake, I really do hope you can find a way to find some good in your life.
And be genuine... And I am when I say it. The first few times I wasn't I really did it more as a total shocker, but then honestly I realized I meant it. I also realized it allowed me to forgive and move past the hurt and anger, because clearly someone once hurt them once too, and honestly if I continue the anger, I'm just continuing the cycle. Best of luck.