It really ought to be accepted to simply say "brother". When we get to other relations, I don't imagine we'll be asked to specify "paternal uncle who is younger than my father" as a translation for shu-shu.
@Mirian - since you are arbitrarily assigning meanings and culling others' vocabulary, I'll pay you the same compliment. Remove "is" and "he" and "ing" from your sentence.
It should be "My younger brother tall but he good look" :-) :-)