No, the word John's is a noun, a possessive, proper noun, the name of a person indicating something belongs to this person by use of the apostrophe s ('s) at the end of the word. A proper noun is always capitalized.
A pronoun is a word that takes the place of a noun in a sentence.
Examples:
Val Johns's birth name is Valjean Johns.
Daniel Johns's birth name is Daniel Paul Johns.
Margo Johns's birth name is Jessie Margaret Johns.
Cort Johns's birth name is Cort Maclean Johns II.
Hugh Johns's birth name is Hugh Richard Lewis Johns.
Stratford Johns's birth name is Alan Edgar Stratford-Johns.
Johns Hopkins
Barbara Rose Johns died in 1991
Pappa johns.
most definetely she is johns offspring
male urologist not at st johns
Helen Johns was born in 1953.