Your father's father's brother is your great uncle.
Great Uncle.
None. There is no relation through "my friend"
Your fathers brothers are your uncles. You are their nephew, or niece.
No relation
This could be a) your aunt on your mother's side (i.e. your mother's sister) b) a wife of an uncle who is your father's brother (an aunt by marriage).
Your father's brother is your uncle.
Your fathers brother is your uncle.
Brother-in-law
brother
Brother in law
Your brother or brother in law
uncle