What is an uncle brother?
Keeping this in consideration, can someone be your uncle and brother?
For someone to be your brother, they must have the same set of parents as you. To be your uncle, they must have the same set of parents as one of your parents. There's no overlap there. That's still only a half-brother, since you and he have different fathers.
One may also ask, what do you call your uncle's brother?
So if you consider your spouse's uncle to also be your uncle (by marriage, of course), then his brother would also be an uncle. If, on the other hand, you are talking about the brother of the husband of your spouse's aunt, there is no relationship between that person and your spouse, therefore none for you, either.
Uncle (from Latin: avunculus the diminutive of avus "grandfather") is a male family relationship or kinship within an extended or immediate family. Uncles are second-degree relatives and share 25% genetic overlap when they are the full brother of one of the biological parents. An uncle is the brother of a parent.