According to the 1930 Federal Census, in Pawling, NY. Katherine L. Treat was about 4 years old living with her grandfather, Daniel Linehan. Also living with her were two of Daniel's children. Theresa and Charlotte Linehan. Daniel's wife Catherine Murphy had already passed away.Theresa and Charlotte had other siblings. Marguerite who married a Morey, Loretta who married a Labounty, and DAniel. They had another daughter Mary and possibly a son named Edward.
I suspect that Katherine L. Treat may have been the daughter of Mary Linehan. Or the other theory could be maybe she was the child of Theresa or Charlotte. Katherine was born around 1926, in Connecticut. She could still be alive and married.
I do know that Daniel Linehan had a brother Michael who lived in Connecticut, he and his wife Mary Ellen Burns, had two children, Francis(male) and Nora C.