Catalyzes the conversion 3-sulfinopropanoyl-CoA (3SP-CoA) to propanoyl-CoA by abstraction of sulfite. Does not show dehydrogenase activity. 3-sulfinopropanoyl-CoA + H2O = H(+) + propanoyl-CoA + sulfite Binds 1 FAD per subunit. kcat is 1.1 sec(-1). Homotrimer or homotetramer. Belongs to the acyl-CoA dehydrogenase family.