As long as he keeps to the agreement and turns over the chemical weapons he won't be touched. This will go one of either two ways, first is he hands over the chemical weapons at which point they are destroyed, he is able to keep his presidency, his regime stays in power, Islamist are crushed, world is a little safer and the UN gets to feel important. The second is he tries to keep chemical weapons or tries to deceive us in some way and that will most likely end up with an army regiment launching some in a heated moment and in turn that will be the end of his presidency, country, life and probably the lives of his entire family which if lucky will be taken in an American airstrike and if unlucky at the hands of the Islamist groups.
I hope he is as smart as he seems and doesn't screw this opportunity up.