Parents might not be the best option. Maybe neutral person is better. Or official server could give him divorce papers. Personally if I ever had such situation, I’d ask my brother or one of my nephews to be present, they would be excellent. Do you have a brother in law or male cousin or uncle?

What could he possibly know that would make your parents think of you differently. There’s nothing I could learn about my daughter that would make me think of her different. If she was secretly a member of a Nazi Party? Maybe. Lol It’s unlikely I’d not know she had extreme views though. Who cares what he shares with your parents. And who cares what they think. We are old enough to be who we are and not worry what others think. They might not even listen to him.

Actually sometimes older generation is more tolerant than we give them credit for.