Hello, Does you Dad have any white or red patching in his mouth, upper pallet?sores on tonsils, cheeks, or tongue? I had no pain or symptoms when my Dentist found  a white leasion on my tonsil and white flat patching on the roof of mouth and tongue.  I had squamous cell Oral mouth cancer of the Oralpharnax. Or  Head and neck cancer. No pain and no idea I had it. Thank God for my Dentist who found it. It can and does spread quickly to lymph nodes in neck.  Just a thought.  Good luck! God Bless .  ... View more