When to capitalize family names such as, Grandma, Grandpa, Mother, Father, Uncle.

Capitalize grandpa when it substitutes for the real name:
  Let’s go to Grandpa’s farm today.

Capitalize grandpa when followed by a name:
  Let’s go see Grandpa Bill.

Do not capitalize grandpa when it could refer to anyone:
  There are many grandpas at the retirement home.

Do not capitalize grandpa when preceded by a pronoun:
  I will go see my grandpa today.