ANSWER:

He must not give zakat without your authorization and prior consent. Otherwise, you have to pay it again and he has to give the money back from his own pocket. 

As follow up Question According to my wife his brother my in-law is paying Zakat yearly what ever he is possess including our money with him. (We are in Abroad) Q:Can he pay Zakat on our behalf? its permissible? are we liable on it?

Zakat |