While it is possible any death certificate may not have the parents' names listed it is far better not to assume. Sometimes the only place the parents' names can be found for a person is on a death certificate (in my experience not having the parents' names listed is very much the exception rather than the rule). Unfortunately for you Kansas death certificates are restricted. Pennsylvania was like that until we got the law changed. In a few months the older Pennsylvania state death certificates are due to start appearing online.
One source you may want to try is to check with the church he was a member of and see what they have in their records on him. Also check with the cemetery office where he is buried for the same reason. His burial entry in the church or cemetery records may not have his parents' names but you never know. His obit may be the same way, but it might list surviving siblings which can be extremely helpful. And in small town newspapers they may have entries like John Smith was in town from Dallas, Texas for the funeral of his brother James. A local historical society or library may be able to help you locate the newspapers existing at the time.