Yes, I think Wormtail will do something relatively small, but nonetheless important. He is not brave enough to really attempt open rebellion against Voldemort. He may, however, help Harry in his search for the Horcruxes by providing information. Of course, he being the weak wizard he is may just be blasted off the face of this earth for it. Perhaps he is one of the deaths....certainly one of the lesser evils in my opinion.