Qatarisun is indeed correct. If your friend is caught, he risks his license, deposit, arrest and deportation. Two guys at Education City were deported 5 years ago. They both had licenses, but they went to QDC during lunch in one car and upon their return to work, then transferred the second fellow's purchases to his own car. They were observed and reported, arrested and deported (I'm a poet and didn't know it).

Our company lawyers have advised that CID has been called when someone has spotted booze in cars parked at shopping centres (presumably, they had stopped enroute to their homes).

Do people buy for other people, I'm sure there are. But you and your friend should be aware of the consequences no matter how improbable they may occur.