Reminds me of the Ray Stevens song, Im my own grandpa.
do the math.
man marries woman.
man's father marries woman's daughter
man and woman have a son.
son becomes brother of man's father, cause man's father is married to woman's daughter.
man's father and woman's daughter have a son.
man's father and woman's daughters son is brother to man because man's father is married to man's mother, and is the woman.s grandchild.
Since, man is married to his grandmother, and brother to his own grandson, he is his own grandpa.
Damn that's complicated.
So this kid, has a mother that is his grand mother also, hopefully, the line of the kid's father and mother/grandmother end there, or this is gonna get weird.