Re: My father in law flipped
Your prospective FIL was wrong to present the pre-nup. The would be considered "under duress" and may in some states annul the agreement. Do research that for yourself.
Is this like Thoroughly Modern Millie (with Mary Tyler Moore, great movie) or did you always know or at least have an idea that your fiance would come into some money fairly soon?
In any case, this is an issue that she should present to you AND own, not let her father do the talking. You're not marrying him. But he will be accessory to your marriage, so give it some thought.
I hate saying, but it will be worth it here: Talk to a lawyer. Is she really going to come into that much money? Plus, what's her financial position now? Student loans? Or did her parents pay for everything?
Has she finished at least an undergraduate degree or will you be hit for that cost?
One thing is certain, he started it. Now that he has, ask enough questions so that you can make an informed decision.