partition action is your legal path forward if mediation doesn't work, and it basically forces a sale through the court system when co-owners can't agree. my uncle went through this after his mom passed - two siblings wanted to keep the house for sentimental reasons, one wanted the cash, and it got ugly fast. the partition lawsuit ended up costing them maybe 15-20k in legal fees between everyone, plus court costs, which ate into what they'd have gotten from selling anyway. before you go that route though, consider whether your resistant brother might budge with a mediator or if there's something deeper going on - sometimes people dig in about property for reasons beyond money, and a neutral third party can help figure out what's actually blocking the deal.