I think your best bet would be to find Robert's death certificate.You may not have the certificate #, but you do have an exact date of death.The certificate would give you some good info. like name of father & mother & his burial.From the cemetery records you could find some other info. you did not have.
You can also contact genealogy groups in the area where Robert lived, they can offer suggestions to you.
On the Topeka & Shawnee Co. Public Library site, there was a Robert Fitzpatrickdeath 11-21-1921 Obit on file from the Topeka State Journal.Then a link for an Obit request Form.There maybe a fee.
Sometimes you just may have to pay a fee for the info you want. Fitzpatrick is such a common name you can spend hours looking for a needle in a haystack.
I'm glad to be of some help.I have worked on my family trees for a number of years now, and along the way I have had ALOT of help.So, I wish you good luck!