Legal analysis: 1. House purchase contracts generally require the signature of the purchaser, which is a citizen’s right. Because the contract law stipulates that the contract shall take effect after being signed by both parties.

2. If the home buyer is indeed unable to sign due to special circumstances, he may entrust another adult citizen in writing to act as his agent to sign and seal.

3. As long as there is a written authorization from the home buyer, the agent’s signature is valid.

Legal basis: Article 469 of the "People's Republic of China and Civil Code" The parties may conclude a contract in written form, oral form or other forms. Written forms are contracts, letters, telegrams, telexes, faxes and other forms that can tangibly express the content contained therein. Data messages that can tangibly express the content through electronic data exchange, email, etc., and can be retrieved at any time, are deemed to be in written form.