As to your questions, I have no information as to whether or not George remarried.His paper trail ended with the 1930 Nebraska Federal Census.
As to when he died and where he was buried, you probably have access to the most definitive information.George is not a direct relative of mine.In the event you don't have the information, my guess is that he is the George Stilwell listed in the Social Security Death Index who died February of 1985.The address of record to which the final benefits were sent was Grand Island, Hall County, Nebraska. The date and month of his birth matches his World War I draft registration.His year of birth listed in the SSDI is 1898 which is one year older than that recorded on his WWI draft registration.The difference in the recorded year is not an uncommon event.
If this George is the one you are looking forward, I suggest you check on available genealogicl resources in Grand Island and with the appropriate state agency to obtain his death certificate. As a direct relative, you would probably have an easier time obtaining a copy of the document.