comma use

[jflooking]

I have a question about comma use.
Is the comma necessary in a sentence like this?

1. This is my brother, Thomas.

2. She doesn't like Thomas, my brother.

Is there any difference between British English and AmE, in this case?

[SoothingDave]

For #1, I like the comma. Some people will claim that "my brother Thomas" means you have no other brothers and "my brother, Thomas" means that you do have other brothers. Or is it the other way around?

I don't think people intend to put that much meaning into punctuation.

For #2, I think the comma is necessary.