If there is any question to the validity of this claim, contact the credit union before contributing any money. And if anyone has already contacted them, could you please post the results of your conversation?
The credit union is clearly legitimate, as it turns up on the Infospace directory at the address and phone shown in posts 5 and 6. If the Robert Jenkins Family Fund weren't legitimate, I'm quite confident that the credit union would return the contribution to the sender (as well as notify police, if they received a flurry of donations designated for a phony fund). Donate away:
Robert Jenkins Family Fund
c/o Tulsa Postal Federal Credit Union
1419 S. Denver Ave.
Tulsa, OK 74119
918-582-1965