All I'm trying to say is, he doesn't need your birthday presents. If you do something l'iluy nishmaso, then yes, it's a nice thing to do. But a birthday present??
Maybe find out if he needs or wants something before deciding on his behalf. Many wanted to give the Rebbe presents, and he made it clear what kind of presents he would like. I'll give you a hint, it involves the study of certain books and the performance of certain rituals.