My father was from Syria, immigrated ~30 years ago and he has a lot of input as to what's going on since I'm sitting with him rn watching the news.
Tl;dr, yes Assad is a questionable man, but he's literally the best person Syria could put in charge even though their family ruled for a quite a while. If Assad gets overthrown, the country is gone. Over there, there is no concept of democracy and people were generally happy with life there before all this shit happened. There will never be a resolution for quite some time. "Destroying ISIS" isn't realistically possible in syria since nobody has a flying clue who is who anymore. It's made of rebels, ISIS, and the Assad regime.