If you weren't terribly close - haven't seen him in a long time - and he's one of those "distant" relatives that all families have, I think it would be fine if you sent a card, some flowers and perhaps called one of his closest survivors to explain that you only have "x" amount of time you can take off from work and you will need that time to see your brother and determine if he needs your help..
Each of my parents came from a very big families - my DH came from a very, VERY big family - and I kid you not, if we went to every wake and funeral of a distant "family" member, it would have been impossible to carry on a normal life - there just wouldn't have been enough time..
I think if you explain the circumstances, other family members will understand..