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 fathers brother is your uncle.
Your father's brother is your uncle.
Brother in law
Brother-in-law
brother
Your brother or brother in law
your brother's daughter is you niece