As not everyone uses facebook, it would be wise to write up briefly but clearly your friend's need for a transplant, and basic information about living donation (including where to get more information, especially about the risks involved, before deciding to offer or not.) Get that information to your friend's relatives, neighbors, co-workers, club members, church/synagogue members, old alumni, local newspapers, etc. Some donors have stepped forward after reading about someone's need in an alumni newsletter, a church bulletin, or even on a supermarket bulletin board. So get the word out as extensively as possible.
best wishes,
Fr. Pat