Here is some information below. Please not when researching that Polly and Mary Thornton are the same individual
1835 US Pension Roll for Renesselaer, NY
Here is where he is buried. https://www.findagrave.com/memorial/14746958/william-thornton
Wife Polly like you mentioned. https://www.findagrave.com/memorial/14746970/mary-polly-thornton
Dear Tracy Reinhardt,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the following file for a William Thornton of Rensselaer Co NY: Revolutionary War Pension and Bounty Land Warrant Application File W. 20,089, for William Thornton, New York (National Archives ID 144331759).
For additional background information on veterans homes see the webpage of the National Park Service for the History of the National Home for Disabled Volunteer Soldiers.
We hope this is helpful. Best of luck with your research!