You could probably contact him on the phone, or via skype if you are tech savvy.
If you mean the name of the relation between yourself and your maternal uncle's son, that would be a cousin (first cousin to be exact).
Your cousin in law
Your uncle's son is your first cousin.
It means you have (or had) at least two uncles and at least two great-uncles, and that is all it means.
Your uncle/aunt's son/daughter is an adult and you are still small, your uncle/aunt's daughter had a child, and that child will call you uncle. Uncles/aunts are your dad/mom's siblings.
Your uncle's grandchild would be your second cousin because his grown son or daughter would be your first cousin.
your uncles son is your cousin
Yes, Florence Nightingale had three maternal uncles: Samuel, Roger, and Luke Smith. They were important figures in her life and supported her in her endeavors.
His great uncle
great uncle
I call them my uncles
The son is the maternal grandson of the mother of the father.
Nieces.