Scott originally agreed to take risks with Matty's life in order to diagnose him in time to be a bone marrow donor to his brother. However, as Matty got worse with no diagnosis, he and Claudia agreed to a 4/6 marrow match instead. Unfortunately, this resulted in Nick getting graft versus host disease.
With both boys getting sicker and Nick seemingly unsavable, the team suggested that Nick be infected to assist in the diagnosis of Matty. However, Scott and Claudia refused.