--- In firstname.lastname@example.org
> Can anyone give me the old norse for this?
Google turns up a lot of Modern Icelandic examples of both:
litli bróðir minn (1990)
bróðir minn litli (52)
Also a few with: hinn litli bróðir minn. I don't know if that adds
the same kind of emphasis as English "that little brother of mine".
Perhaps the most likely way to say it in Old Norse would be:
bróðir minn inn litli