I don't think trauma experienced by children at any age can be discounted on how it may affect the memory of their lost parent.
For example, I just watched a program on the brutal Ohio murder of Ashley Biggs in 2012 by her baby daddy (Cobb) and his then wife Erica Stefanko. (There's a thread for this case).
Ashley was delivering pizzas for Dominos when the murdering couple lured her to a dark office park in the guise of somebody working late at an office in the park.
This case also involved a custody battle over Cobb and Ashley's 7 yr old daughter, Grace. (Ashley granted custody and dad had regular visitation). Cobb took a plea deal for the murder but his then wife Stefanko was not arrested until years later.
In 2020, Grace, then 14, testified during the trial of Stefanko that she had no memory of her mother, Ashely. In 2024, at the retrial of Stefanko, Grace now age 18 testified again that she has no memory of her mother. Here, the child was 7 when Mom was murdered, and she was was raised by her grandparents after the loss of both parents.
Seriously, who's to say what traumatized children of any age remember including the Markel boys. MOO