Depends on what side of the family your cousin and great-grandfather are on...
If your cousin is not descended fro your great grandfather, they are not related.
If your cousin is descended from your great-grandfather, and your cousin is not a "removed cousin" as in second cousin, once removed, etc., then your cousin is your great grandfather's great grandchild, as are you.
Your cousin's cousin could either be your cousin or no relation at all.
He is of relation as a cousin-in-law.
If your first common ancestor is your great great grandfather and her great grandfather, then the two of you are second cousins, once removed.She and one of your parents are second cousins to each other.Her children are your third cousins.
Well, your cousin's brother is also your cousin, and a cousin's son is also your cousin.
Your cousin. You are that person's second cousin.
Second cousin
They are your cousin-in-law.
Cousin in Law
Your cousin-in-law.
still your cousin
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.