what is my mater name
He is your grandson. If his father is your son, he is your grandson.
Second cousins.
Your grandson is the great-nephew of your brother.
Jin is the son of Kazuya and Jun, and therefore Heiachi's grandson.
You are third cousins.
No. Louis XVI was the grandson of Louis XV. The series of brothers came next - Louis XVI, Louis XVIII and Charles X.
The possessive form is grandson's.
Your first cousin's grandson son is your grandson's third cousin. Your second cousin's grandson is your grandson's fourth cousin. Etc., etc.
A rather convoluted string of no value. The answer is you are, or your sisters or brothers are, or your first cousins are.
The grandson of your first cousin and your grandson are third cousins to eachother.
Your grandson and your brother's grandson are second cousins to each other.
Your father's grandfather is your great grandfather. Your great grandfather's daughter could be your father's aunt and your great aunt. The grandson of your great aunt is your second cousin. However, your great grandfather's daughter could also be your father's mother and your grandmother. Then you, one of your brothers, or one of your first cousins, is the grandson in question.