A similar case would be when I want to transfer my shares to my kids.
Your broker can do that but tax complications come to play. All gains made by those shares will be for your account until your demise.
My case:
I donated R270k to my wife and she bought shares with it. The capital is hers and allowed tax free by SARS but any gains made are for my account.
I think the OP's seller wants that Capital loss for his benefit.