At the quastion:
"Do you have a family member who is a Canadian citizen or permanent resident and is 18 years or older?"
is my cousin (son of aunt) a family member? yes or no... if yes is that a disadvantage that i have a family member there?
Just check out the ? at the end of the question, it will expand to let you know that a relative means spouse, or common law partner or dependant children or children of dependant children. So I guess you can write NO for that for your cousin.