Congressman Sean Casten remembers late daughter, Gwen, as "happy, healthy, well adjusted young woman"

CHICAGO (CBS) -- Two days after the sudden death of his daughter, Gwen, U.S. Rep. Sean Casten described the 17-year-old as "a happy, healthy, well adjusted young woman who was looking forward to starting her freshman year at the University of Vermont."

In a post on Twitter, the congressman reflected on his daughter's passion for music at Downers Grove North High School, and her political activism, including her work with March for Our Lives and Black Lives Matter.

"She was inspired by the student efforts in the wake of the Parkland shooting to create an Empowerment Club in her high school which became one of the largest clubs at DGN, focusing on everything from gun violence prevention to environmental protection to LGBTQ allyship to organizing Black Lives Matter rallies to registering students to vote," he wrote.

Casten said his daughter died after going to sleep Sunday night, after having dinner with her family, and spending time with her friends.

"The only thing we know about her death is that it was peaceful. And the only lesson we can take from that is to savor the moments you have with your loved ones. We want purpose. We want to believe in a brighter tomorrow. But the only thing we can control is our present," he wrote. "We are grateful to all who have reached out with thoughts, condolences and help. To all asking what they can do, we ask only that you live your lives as Gwen lived hers. Savor the moments. Use every ounce of energy you have to ensure a better, more tolerant, more generous, more loving tomorrow. Not because you know that tomorrow will come, but because you know that someone else's will. Lead with Love."