Marriage certificate issue, help please?!

So, I was reviewing what was needed to get our marriage certificate, and they have an option to partially fill it out online. They need mother and father's birthplace from my FH. He hasn't heard from his mother since he was 8, and he isn't on good terms with his father, for very good reasons.

I checked his birth certificate to see if it was listed like mine but it's not. What do I do now? Have any of you had an issue like this?