Your grandmother's brother is your great uncle.
Your brother's father-in-law is not related to you unless you and your brother married sisters from the same family. Then he would be your father-in-law, too.
There is no word in the English language for a relationship between grandmothers of related grandchildren
You are not related as you do not share a common ancestor.
Your grandmother's brother is your parent's uncle. The uncle's child would be your parents first cousin. You would be second cousins.
no he is my uncle I think I would know he was my grandmothers brother Judy M.Osbourne
First cousins once removed. They would be your parent's cousin.
If you have no siblings but your daughter has an uncle, he is the brother of your spouse, your brother-in-law.
That depends, if you are referring to grandmothers as in a group or multiple grandmothers no, if you implying it belongs to a singular grandomother it would be "grandmother's" and finally if its something possessed by multiple grandmothers it would be "grandmothers'"
Your great grandmother's brother is your great great uncle. Your parent and the grandson of your great great uncle are Second Cousins. Therefore you and the grandson of your great great uncle are Second Cousins, once removed.
If your great great grandmothers were sisters, your common ancestors are your great great great grandparents. That makes you 4th cousins.
Your son-in-law's brother is your daughter's brother-in-law but is not related to you.
that would be your grand uncle