Dear
@Chestnutsunfish,
Thank you for your insightful and greatly compassionate posts.
The testing of the jacket and the car for DNA of Abby and Libby will all come out in the evidence presented at trial.
With blood mingled with water on his clothes, the chances of any (even miniscule) drops of blood will be found in the car, (the side of the seat, the back of the seat, anything in that area that he touched or sat on his clothes brushed against) will light up with luminol.
Every single piece of material from that car seat as well as the floor of the car will be scrutinized and tested for DNA. Car handles, plastic -everything will be tested.
With all of the advances in DNA testing - especially since 2017 - leads me to believe that Abby and Libby's DNA will be discovered in the car.
I expect the DNA evidence at the trial to be fascinating.
JMO