I would say get rid of that L-R panning on them. Put the main track down the middle, and if you have any other tracks for fullness pan them only slightly to one side. The mic actually sounds fine to me. The vocal performance itself kind of sucks. I can tell that these were done quietly with no actual energy. Good screams are LOUD. Other than that, I would recommend maybe adding a little distortion or overdrive to them. Just a touch to make them warmer.
And re-do the high "screams." I can hear the singers throat rotting away from his poor technique. You end up with that weak straining sound that sounds like someone is bleeding from their throat. High screams still come from your diaphragm, just like low screams. They are still strong and powerful, the only thing that changes is the shape of your mouth.
