Your mother must have had the patience of a saint to not go mama bear on your uncle.
My father and my uncle were friends in the Marines in the South Pacific during the war. When his friend got a "Dear John" letter from his girlfriend, my father gave him his sister's address and they began corresponding and got married in 1945. They had two children, 7 grandchildren, and I don't know how many great-grandchildren by now--none of whom would have been born if my father and my uncle had not been friends in the Marines.