Complex sentence: This is due to Brendan Fraser playing Ben Sullivan, his best friend and ex-brother-in-law, being unavailable to appear in the episode who had been visible to Dr. Cox throughout My Screw Up.
Split into simpler sentences: This is due to Brendan Fraser playing Ben Sullivan, his best friend and ex-brother-in-law, being unavailable to appear in the episode. He had been visible to Dr. Cox throughout My Screw Up.