I am trying to find my family of origin.
My dad died several almost 15 years ago before DNA was a common thing. He was adopted and never knew anything about his birth parents and he never wanted to know so he never tried to find out. I have since identified his mother (my grandmother) and established contact with the family although my grandmother indicates that she doesn't know anything about my dad's father. She gave up a baby before my dad was born and put him up for adoption too. Through Ancestry, I have found 2 more 'aunts' who appear to be my dad's half sisters, both of whom were given up for adoption at birth, after he was born. They do not know their parents either. These two aunts and my father were all born within 5 years of each other. After years of research I have been told many times that my great grandfather had incestual relations with all three of his daughters, one of which was my grandmother (Dad's mom) which resulted in several children, all of whom were placed for adoption at birth.
I match to my dad's two siblings at 784 and 933 cM respectively. This would indicate 1/2 aunt which would make sense if they all had the same mother - my grandma - and different fathers but this doesn't seem to fit the story. It would also make sense if they all had the same father but different mothers (one of the three sisters) although I feel like there would still be a higher relationship possibility because they would share the same parent DNA as well as the common great grandmother's DNA (the mom of the three girls)....right?
If the story I've heard is true, how would this affect the DNA relationship I have with these aunts, or would it at all?
Can my DNA results help me figure out who my grandfather is?