On Wednesday, Casten shared more details about Gwen’s passing on Twitter.
Casten says Gwen was a happy and healthy young woman who was looking forward to starting her freshman year at the University of Vermont.
He says on Sunday, the family had dinner together and then Gwen went out with some friends. She got home, said goodnight to her family and then didn't wake up Monday morning.
"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," Casten said.
"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."