Can you prove it was chemo that gave your dad 24 years?
Chemotherapy is literally a lethal dose of radiation! It kills everything in it's path and often kills the patient.
That is the extent of the treatment, it's insane!
Medicine has been like this for a long long time... Bloodletting used to be a respectable and widely accepted treatment for many ills... They would let a huge quantity of blood out and if the condition didn't improve they would let some more out... If the patient died they would lament, if only they'd let more blood out, and sooner!!!
Stand back a couple of paces... Is chemo any different?