An apple a day keeps the doctor away. So what happens if a doctor had an apple?
-- he would go POOF!!!! (and disapeer)-- Then he would be healthy. He won't become schizophrenic. He will forget all his medical training and become just another mortal. The phrase means that if you have an apple per day you won't have to go get a check-up. So if a doctor had an apple then he won't have to go get a check-up. If The Doctor had an apple then nothing would happen. Unless he was just about to go on an adventure. He might dissapear
There is no pronoun in the saying "An apple a day keeps the doctor away." A pronoun is a word that takes the place of a noun in a sentence, for example: "It keeps the doctor away." (the pronoun 'it' takes the place of the noun phrase 'an apple a day', which is the subject of the sentence) "An apple a day keeps him away." (the pronoun 'him' takes the place of the noun 'doctor')