Establishing democracy in western countries took a few civil wars too. The American Civil War, the French Revolution, the English Civil War, World War 1, World War 2, the Spanish Civil War, the Russian Civil War, etc.

It's not "Arab tribalism" that is the problem. Assad was frightened he would be hanged like Saddam or lynched to death like Gaddafi. He had no options but to fight to death. 

Guaranteeing a safe and secure exit for a dictator and his family is a must, however revolting the idea is.