Okay. I've done a (very) little reading on Tanzania. I don't know anything about the orphanage or your friend, so this may not be a useful suggestions, but has your friend considered reaching out to the LDS Church?

I'm not a Mormon, but I've know many of them. They're big on charitable works (most religious groups are) and a majority of them (that I've encountered) are cyclists.
If there are Mormon missionaries there it's a safe bet there are bike supplies, and people with the knowledge, ability, and willingness to use them.