Knut Ossian Nyblade (Nyblad)

My grandfather and three of his brothers emigrated from Sweden. My grandfather came to England and his brothers went to the U.S.A. I have located what happened to two of them but the third has been a mystery for very many years. Now I have strong evidence that Knut Ossian Nyblad(e)was in the U.S.1900 Census for Dawes Precinct, Thurston County in Nebraska. I've no idea where this may be in Nebraska as I have not yet found a map of the area. He was said to be working as a farm labourer. To the question of Naturalisation, the answer is 'Pa' and I have no idea what this means. He was born in March 1870 (the Census says 1871?) and was single at that time.
His mother died in 1904 and her Will states that Knut was living in 'some unknown foreign place'. He had not been in contact his parents for some time. My feeling is that he probably died between 1900 and 1904 and because he was single and alone, there was no-one to notify his parents of his untimely death. I would very much like to find evidence of his death or anything else about him but I am not sure what records exist or how to go about it.
Can anyone help please?
Margaret E. Nyblad Brown