Dr. Irwin Schatz, father of U.S. Sen. Brian Schatz, has died.

The cardiologist was a former chair of the University of Hawaii Department of Medicine and led the medical school’s residency program for over 20 years.

He is known as the only physician to have complained about ethics of the Center for Disease Control’s Tuskegee Study when it was originally published. The study involved denying healthcare to hundreds of black men who were suffering from syphilis.

He received a Distinguished Alumni Award from Rochester, Minnesota’s Mayo Clinic in 2009.

The Honolulu Museum of Art, where Irwin Schatz served as a docent, acknowledge the doctor’s passing in the organization’s newsletter and wrote that it was an honor to work with him.

“He was a wonderful, brilliant man who was very caring and had a great sense of humor,” wrote education curator Betsy Robb.

Read more about Dr. Schatz below:

Hawaii Dr. Irwin Schatz’ Stand Against Racism Resonates Decades Later