Assad is a tyrant and hates Israel. The 'stable' thing about him is his continuing hatred of the peple of Zion. It is consistant and unabating and predictable which meets the West's criteria for 'stability'. He is a patsy for Iran. There, that is all the good things I can think of to say about him in relation to Israel.
Jordan foreign minister says to speak with Kerry on Israel-Palestinian conflict (Reuters)
from the article: Assad's fall could deliver Lebanon to Iran and Hezbollah