Yes, of course. They aided Libya, why not Syria. The differences in both civil wars are tiny. Of course danger exists that the aid will go to Hezbollah and Al-Queda, the infamous terrorist groups, but Assad is much worse than the terrorist groups as he possesses much more power. However, the western nations should only aid with small weapons and humanitarian needs, never should they send troops on the ground - that would be another Korea or Afghanistan- another mistake!
They should because people there started peaceful protests that were violently crushed. They should because human rights have been violated. They should because it is the right thing to do!