Typical consumerism. I have siblings who did the same for a fancy bed. These people are mostly helpless. And you're only an employee.. I'm sure it's not great to try to turn a customer away from a sale right ? Even as a sibling, unless I'm ready to start a family war there's no leverage.
ps: the 40yo man might have sold or made use of the other iPhone. I hope he did not just pile them up in a drawer.