Well crap, while everything seemed promising initially, last night we got the response from him that we expected. He texted my wife saying he gave it thought and doesn't ever want to see me again because he's "lost all respect" for me and fears he might attempt to harm me out of anger for hurting his daughter.
My wife responded that it's not my fault nor our oldest child's (who is non-binary), that science has proven this is real, and that he should be open minded. His subsequent responses were alt-right garbage upon garbage and even going so far as to tell my wife that her mom was rolling over in her grave. My wife to her credit stood up for me and our oldest repeatedly, calling him out on his ignorance and hatred.
Unfortunately, the exchange ended with her telling him to stay out of or lives and have no further contact with us. He's now been blocked on social media and through our phone carriers. While my wife is putting up a strong front, this is not a good situation at all. I've been struggling with guilt over being the cause of this, even though my wife and everyone else tell me it's not my fault. My biggest concern right now is her. The only family she really has left now is her grandmother (who is super supportive of both of us).
Ugh, not the result we wanted at all, but sadly not a surprise.