Goodness, quite a bit of tragedy there. I tend to really look at the human side of things and what people must have felt. The poor mother, losing her husband during the Depression with 2 kids and a baby on the way (given the age gap between sibs you almost have to think 'oops' baby!) and then all three children losing their mother not long after. And then how confusing and upsetting it must have been for Betty to lose both her younger brothers and Carl to have to move families at that age. Not to mention Lee and the trauma of losing your mom as a toddler, as well as your older siblings. At 16 months the permanent memories would not have formed but it would have been a highly traumatic event.
Sadly those attitudes toward adoption were so common in the 1940s -- keep it a secret, etc. Every adoptee I have ever heard of who found out years later and were never told was very traumatized by the discovery.
As an adoptive mom I am just really sensitive to that. Fortunately now there is more openness and less secret-keeping.