In-laws want postnuptial signed??

Hi ya’ll - my husband came home with an agreement his parents’ lawyer drafted. It was basically a postnuptial agreement. My in-laws are not wealthy. My husband is not wealthy. I’ve financially supported him since we’ve been married (5+ years ago). We had to buy property from my in-laws a few years ago bc they couldn’t afford the payments. This agreement gives them all rights to it. If my husband dies or we get divorced and property is given to me, I have to sell it back to my in-laws for less than its value. Wouldn’t go to our kids. This is insane right? My husband told me I need to just sign it bc his parents do a lot for us and i should just sign what they ask. The fuck? They don’t do shit for us except stir up trouble like this 🤦🏻‍♀️