Complex sentence: He is currently the solo executive producer of the CBS series' which he took on following the departure of Carol Mendelsohn, he has also wrote for the TV show "NUMB3RS" which during it run he acted as executive producer.
Split into simpler sentences: He is currently the solo executive producer of the CBS series' which he took on following the departure of Carol Mendelsohn. McGill has also wrote for the TV show "NUMB3RS" which during its run he acted as executive producer.