I knew this doofus wouldn't apologize.
Just be an adult and admit you shouldn't have made a remark in such poor taste about someone's family member, and everything will be all better.
If I make a tasteless remark and someone challenges the remark, and the challenge is sensible, I'm always willing to take it back. That's because I successfully went through puberty over 40 years ago.
I don't think you have the balls to apologize though, which is the most ugly thing of all.