I feel like the more likely scenario is that someone (probably a title company) did their due diligence, recognized that the children had or may have had some legal interest in the property, and contacted them directly to get them to sign deeds so that the buyer can have clear title. It’s entirely possible that the kids still didn’t have the energy to talk about this, but by not agreeing to some dollar figure or just signing away their rights to the property entirely, the closing would not have gone forward. They were up against a clock of OP’s creation. OP is probably lucky they all actually cooperated. Depending on where he’s at, if the deal fell through, he could’ve had the closing fall through, have this have to go through probate, AND been sued by the buyer for trying to sell a property he didn’t have clear title to.