About the property dispute-after the death of the seller, the seller's family refused to admit that they had sold the house to the buyer. What should the buyer do? Can I go to court to sue?

Real estate belongs to real estate, and its ownership is based on property registration. So legally speaking, this house is still owned by A, and this house is also an inheritable heritage. However, according to the inheritance law of our country, the heir should bear all the debts of the decedent (that is, A) within the scope of his inherited property. In other words, you can bring a lawsuit to the court and ask A's successor to fulfill the contract that A signed with you before his death.

Your prosecution can be to take A's children and parents (both heirs of A) as defendants. Ask them to fulfill the purchase contract that A signed with you before his death. As long as the court makes a judgment, you can transfer ownership with the judgment. The most important thing here is the contract signed between Party B and Party A and the fact that Party B has paid the house price. These two points must be proved by sufficient evidence. Then you can basically win the case. But I'm not sure about the specific situation. The other party has many reasons to refute B's evidence. For example, there is a problem in signing the contract between Party B and Party A, and the house payment paid by Party B is not the current market price. You can refer to the provisions of the Contract Law on the impossibility and revocability of a contract. But it's better to find a lawyer. If you want to fight this lawsuit yourself, you must understand the civil law, property law, contract law, inheritance law and the judicial interpretation of these laws by the Supreme Court before you can fight it yourself or hire a lawyer.