My Father Served In Vietnam, He Was Exposed To Agent

My father served in Vietnam, he was exposed to agent orange, he was in the 3 major areas at 3 separate times where the agent orange was sprayed the heaviest and most potent form. he then became sick, was sent back home, during his recovery my mother discovered her pregnancy with my late sister, whom succomed to her illness of arteriovenious malformation, I realize this is usually congenital, but at the time the doctor told my parents there were recent cases and there was an agent orange exposure link to those cases. this was in Oct. of 1983 that she died. I hope to hear your resoponse, she was hit by a car when she was 4, that's when she was diagnosed, they said she wouldn't live past 10 and she died just after her 13th birthday, this has always haunted me. this was my only sister, my only sibling, my father has never been compensated for his service in Vietnam, he has 3 bronze stars and was forever changed by that war. Although, I will always blame the war for my sisters untimely death and for my fathers PTSD, it forever changed the course of my life, I just want to know with your medical training and experience, have you ever saw cases with AV malformation with exposure to agent orange in utero, any correlation that you can say with medical certainty or probability that her congenital defect could be caused by this. we have no family history on either side as far back as I can investigate, not one case of this in Jennifer's family history, that's my late sister Jennifer, she died 7 days after her 13 birthday in Oct, 1983. This has haunted me all my life, I need answers.. Thankyou