(Question) On my fathers side, I dont have a brother and I dont have an Uncle. I do have a male cousin, whom is the great nephew of my father. My father and his grandmother were brother and sister. Can he be useful in any way?

(Answer) It depends. How is this grandson descended from your aunt, through a daughter or a son? Your aunt would have the same mtDNA as your father and would have passed it to her children. Her daughters would have passed it to their children. If he descended from a son of your aunt, testing him won't help you.

(My statement)
Hmmmmm, he came from a son.

Aunt Sis-My father (sister and brother)
Aunt Sis' son-Pete
Petes' son-Ricky

Are there any relatives to test to get your mother's father's lineage?
(Answer) Yes. I talked to my first cousin today, and we are going to ask our grandfather (mothers paternal side) to take the test for us. In addition to him, he has 87 and 91 year old brothers that would also be available to take the test for us.

On your father's side, did your grandfather have siblings?
(Answer) Yes. I am currently looking for them. While alive my father really never was into the 'family thing', but I remember visiting one of my fathers first cousins. My fathers father and his father were brothers.