Malcolm is the brother of Phillip and brother-in-law of Janine.
History
Malcolm's sister-in-law, Janine, was 20 weeks pregnant and short of breath. She wondered if she had gestational diabetes because her husband, Phillip, was diabetic. Malcolm, who is a nurse, came to her appointment because Phillip had to work. Addison said that her blood sugar was fine. Addison listened to her lungs and had Dell call an ambulance because she heard fluid in Janine's lungs. She had diffuse myocardial dysfunction. The added pressure of the pregnancy caused the condition to worsen quickly. She needed a heart transplant. Because the pregnancy was putting extra stress on her, Addison recommended termination. Her husband said she should, but Janine said she couldn't do it.
Janine was put at the top of the donor list, but her husband and brother-in-law were told she had only 48 hours to find a heart.
Phillip later came into the ER with no brain activity. He'd had an insulin overdose that caused brain death. His license revealed that he was an organ donor. They talked to Janine, asking her to take Phillip's heart to save her life. Malcolm encouraged her to take it. They took her in for the surgery, but were stopped by Charlotte King. She believed it was either suicide or homicide and insisted that evidence be collected before the transplant could take place. They waited and Phillip started to become unstable, so they had to rush once they were cleared to retrieve the heart.
After the transplant, Janine's condition improved, though she worried because she suspected that Malcolm might have killed his brother to get Janine a heart. She knew he was in love with her. Addison confronted Malcolm about it, but he denied it, saying he loved his brother. The ME ruled Phillip's death an accidental overdose. Addison later watched as Malcolm kissed Janine's hand in her hospital room.
Relationships
Romantic
He is in love with his brother's wife, Janine. She even suspected that he killed his brother to get Janine a heart transplant.
Familial
His brother trusted him to take care of Janine while he worked. When Phillip died of an insulin overdose, Malcolm was suspected of having killed him to get Janine his heart.
Career
He is a nurse. That is part of the reason why they suspected that he killed his brother, because he would know the dosage required to kill him without stopping his heart.