Individuals with Cystic Fibrosis do not benefit from the transplantation of a single lobe of a lung. The right lung has three large lobes. And the left lobe has two. So donating a single lobe of a lung would do very little good for these kinds of patients. They wouldn't even benefit from a single lung transplant. Cystic Fibrosis that is treated with a lung transplantation involves resecting both affected lungs, and transplanting in a right and a left lung. It is imperative that these patients receive two lungs.
The character that is donating bits and pieces of himself to strangers would have to undergo a psychiatric examination by the second donation. A person giving away vital organs for so-called altruistic reasons would be called into question. His mental stability would definitely be called into question.