Hi there ... just wanted to send you a hug ... it's prob good to see his dr or talk to the help line here or Macmillan free on help line ... as like you we can only guess ... my sister has dimenture so I know how worrying that can be ... how cruel to have cancer too .. but best to get it diagnosed properly... 

hope that helps a little ... sending loving thoughts to you and your dad ... Chrisie xx