Neil Cornelius of Blue Earth, MN., 1920?

I am looking for anyone with information about my grandfather, Neil Cornelius Anderson born Circa 1920.I cannot figgure out who his father was.I was told my grandfather had several brothers but I know no names or if they are still living to contact them.It is possible his father may have come from Ireland but that is unconfirmed. Any clues to these mysteries would be appreciated.
Thanks!