Edit: I got downvoted because some people don’t understand family trees. So imagine this if you will.
My dad’s sister is named Pam. Pam is my aunt. Pam is married to Ron, so Ron is my uncle. Ron has a brother named Jeff. Jeff is not my uncle and is not related to me, except sorta kinda through marriage.
Jeff is my uncle’s brother. But he is not my uncle.
Your uncle's brother is another uncle.
Not if he’s an uncle by marriage.
Edit: I got downvoted because some people don’t understand family trees. So imagine this if you will.
My dad’s sister is named Pam. Pam is my aunt. Pam is married to Ron, so Ron is my uncle. Ron has a brother named Jeff. Jeff is not my uncle and is not related to me, except sorta kinda through marriage.
Jeff is my uncle’s brother. But he is not my uncle.