In the U.S., a limited power of attorney for this transaction would be required. As for what Chinese law may require, your relative will need to consult a lawyer who practices in China or who is familiar with Chinese law.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
Her friend very well may be able to sell her house in China with a notarized letter from her authorizing the sale. I visited China recently to investigate the real estate scene there, and it was little like the wild west. The laws are not transparent - they do not have a functional County Recorder system such as we enjoy here. If nothing else, the friend will discover what the system requires so the proper paperwork can be made.
What concerns me more is that, if successful, the friend will have her money. We enjoy an escrow system here in the US that simply does not exist in China. If the friend gets the money for the sale fo the house, he could make off with the money.
There are reputable brokers in China, including some of the franchises that we have here. Why not check into CB Richard Ellis to see if they would broker the sale or recommend a residential brokerage that could do it for your relative?
I guess I wouldn’t feel lawyerly unless I wrote a disclaimer to this answer – after all, that’s what we lawyers are trained to do. So here it is. Disclaimer: Trying to provide a complete answer to a brief question without meeting the questioner and without getting all the facts is much like internet dating. Despite what you have been told by the person you’ve met online (and don’t they always put everything in the best light for themselves), once you meet them face to face you realize how much has been left out. People tend to bend the facts and there is always the other side to the story. So, this answer is about as valuable as the price that was paid for it. It should not be considered legal advice. It is meant as a general overview of how the law could apply to a very broad set of facts that may not have any applicability to the actual circumstances of the person making the question. It is hoped to provide some understanding of the broad field of law that could come into play. No attorney-client relationship has been formed with the questioner and no attorney client relationship was ever anticipated by my response to this question. I would also like to remind you that I am only licensed in the State of California, and the answer provided is based upon my knowledge of California law.
The sale of any property in China through an agent (your relative's friend) will require much more than a simple note. If the agent is not a citizen of China, it will be more difficult. There are also numerous facts that are not included in your question: does the friend speak Chinese? If so, is it the appropriate dialect for the area the property is located? If the property is sold to a resident of China, will the payment be made in Chinese currency? If so, how will your relative gain access to the funds?
For all of the above reasons, it is important to hire an attorney who is licensed to practice law in China but who is also familiar with U.S./U.K. laws as well. There are many such lawyers in Hong Kong.
The above response does not create an ongoing duty to respond to questions. No attorney-client relationship is formed by this response, which reflects only the opinion of the author. The response should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question and could change if additional facts were made available. The Attorney is licensed to practice law only in the State of California and his responses are based solely on California law unless stated otherwise.