That has been a case of "the enemy of my enemy" as the Al Nusra Islamists had still considered Israel as infidels that need to be eventually be dealt with.

Israel more pressing Islamist threat, Hezbollah, was the focus back then and therefore these organizations were given medical help in turn for agreeing not to kill Druze and to stay away from the Israeli border.

It was quite evident Israel's position as it hasn't tried to fight for Al Nusra when Assad recaptured that area even though it could easily make the Syrian regime forces retreat.

Also, the repeated bombing of the current syrian government forces are probably not due to some outbursting friendship