ST. JOSEPH, Mich. – A Chicago doctor who devoted his career to saving the lives of children died trying to assist two young people who were struggling in the treacherous waves of Lake Michigan over the weekend.

Dr. Donald Liu, his wife and three children were enjoying a weekend getaway at a Berrien County beach on Sunday when he spotted two children in the water who were struggling.

Liu, 50, was able to help the children to safety but was pulled under by a strong current and drowned, authorities and his friends told the Chicago Sun-Times.

“He managed to help them but he got pulled down by the undertow himself,” said friend and colleague Dr. Jeffrey Matthews, chairman of surgery at the University of Chicago Hospitals. “He really died a hero.”

Liu was surgeon-in-chief and professor of surgery and pediatrics at Comer Children’s Hospital. He joined the University of Chicago department of surgery as a pediatric surgeon in 2001 and was made chief of pediatric surgery and surgeon-in-chief at Comer in 2007.

“He was an amazing man,” his wife, Dr. Dana Suskind, told the Chicago Sun-Times. “We are just all in shock.”

Two other men drowned on Sunday as high winds and waves swept Michigan’s west coast.

The other victims were Anthony Joseph Kelly, 41, of Montgomery, Ill., and an unnamed 40-year-old Cincinnati man.

U.S. Coast Guard Petty Officer Brandon Underwood said police officers entered 10-foot seas off Tiscornia Beach in St. Joseph and brought in two people who were trying in vain to reach Kelly.

The officers “were heroic, putting on life jackets, and swimming out there,” Underwood told The Herald-Palladium.

Kelly died midday Sunday.

That evening, the 40-year-old Ohio man died when he went under in a strong rip current in northern Lower Michigan’s Benzie County.

Search crews found his body in 5 feet of water, WWTV-WWUP reported.