I'm not quite sure what you are asking, really. Do you mean that your son has your contact information in the first, "My Contact" card? If so, he should be able to change that by pressing menu->edit.

If you mean that he has a contact saved for you but it will not initiate a phone call, does it have a phone number in the contact?

 

Have you tried adding a contact for you?

 

Well, first, I think by design that contact cannot be deleted. However, he should be able to change it to his own information. And then, as bberryhill0 mentioned, add a separate contact for you with your phone number.

That's what I think you/he should do.