TAR Syndrome genetics

[countrylove]

https://en.wikipedia.org/wiki/TAR_syndrome

I hope I posted in the correct area. I have a question concerning TAR Syndrome. I know it is a genetic disorder, my boyfriend's younger brother has Tar and a first cousin all on his father's side of the family. (boys) WE want to conceive a child but I need to know if he is a carrier. What are the chances? Would his brother just be a carrier or him as well. There are no known cases on his mother's side. No birth defects in my family.