Kirk, there is a "Delphinic" type ambiguity in the previous wording. The last phrase could be interpreted:
1. "He remained hospitalized for most of the time....at Creedmore."
2. "He remained hospitalized ....until his death at Creedmore."
The source is excellent, however, the unfortunate phrasing may not give you the "deffinative" you seek. The best bet is to quote the source dirrectly.
The article in American Biography was written by Arnold Shaw
I am personally prone to hyperboyle and therefore found this quote at the end of the article to be interesting.
"In the New Yorker in the early 1940's, Clifton Fadiman wrote, 'Someday people are going to wake up to the fact that Woody Guthre and the ten thousand songs that leap and tumble off the strings of his music box are a national possesion, like Yellowstone and Yosemite, and part of the best stuff this country has to show the world.'"
His obituary is noted as being in the New York Times Oct. 4, 1967.