He shows up in the 1930 Census as residing In the community of Warren, Niobrara County, occupation listed as farmer.
There does not appear to be anyone living with him. That's about all that is available here on Ancestry. As far as what happened during the 1940s thru the 1950s I am *guessing* he may have given up his farm and moved into some type of care facility in Lusk. If he had no relatives or associates who might care for him, he would have become a ward of the Court so you might wish to get in touch with the District Court in Lusk. Lusk is a small community with great records at the local level. Good luck.