Complex sentence: As he is setting it up, Brian is struck by a reckless driver in a hit and run, and later succumbs to his injuries at the veterinary clinic, with Stewie unable to rebuild the time machine as he cannot acquire a new power supply.
Split into simpler sentences: As he is setting it up, Brian is struck by a reckless driver in a hit and run and later succumbs to his injuries at the veterinary clinic. Stewie is unable to rebuild the time machine as he cannot acquire a new power supply.