The Golan was GIVEN to Syria at the end of the 1st WW. It was not naturally theirs. Go read the history of the Golan to see how many times it was fought for and lost and fought for again and lost. Now it belongs to Israel. If Assad wants to fight for it then that is his perogative.
Car bomb in Syria's Latakia kills at least seven (Reuters)
from the article: Three Syrian tanks enter demilitarized zone in Golan Heights