If someone is on life support with pneumonia and sepsis, is there chance of recovery?

Yes. Yes there is certainly a chance for recovery. In fact most patients with sepsis recover. The real chance of recovery depends on all kinds of details, including any underlying medical problems, kinds of organ failure, etc and should be discussed with the doctors involved in the care of the patient.
Absolutely. Much depends upon their underlying conditions, the causative agent of their pneumonia, and the extent to which other organ systems may have been involved. With the quality of U.S. Doctors and the excellence of our icus, the chances for full recovery have been remarkably enhanced.