A rose by any other name?

At some point months and months ago I started referring to Carter as "Brother" when talking to Caleb. I don't know why I did this but he picked up on this and now calls Carter "bruba". It is quite cute to hear him yelling, "BRUBA!" Recently Carter has decided he doesn't like this name anymore. This afternoon while eating their snack I overheard the following conversation.

Carter: Caleb?
Caleb: Des? (Yes)
Carter: I don't want to be "Brother" anymore. I'm "Ka - TER" (My attempt to give you an idea of his strange pronunciation.)

Caleb just looks at Carter with his cute little smile and is totally clueless as to what "bruba" is talking about.

Carter: Caleb, what's my name?
Caleb: Bruba
Carter: NOO! I'm "Ka-TER" Uhhhhh!!!
Caleb: Uh huh.

Carter: Caleb, what's my name?
Caleb: Bruba

After this repeated several times Carter gave up.

Face it Carter Bugs, you are Bruba to Caleb Poo.