Legal issue regarding power of attorney in China and international law

I have a legal issue with which i was wondering if you could help me. I am a UK citizen and live also in the UK. My brother is in Pakistan and has recently been very sick and is unable to walk or move. He had bought property in Shanghai 4 years ago and would like me to go and sell it and bring the money back home. I was wondering legally if its possible to do that if he gives me the power of attorney and if a Pakistani power of attorney verified by the Chinese embassy in Pakistan would be valid or if there is any other way of doing this. As it is not possible for my brother to travel to China right now.

Could you also explain to me the whole procedure and how long it would take. Also what would be your role as the law firm in this and how much would be the estimated cost for all services including dealing with power of attorney to selling and transfering the money. I hope to hear a response from you as soon as possible.

Kind regards