I didn't watch the testimony ,but based on just the few posts I read here,I think Lee always felt like he was on the outside,like ICA was the favored child.
He watched her get away with everything,including not paying him for the car.CA said in her depo ,of the two ICA was the better student.Lee went through a horrible illness and CA said he was more withdrawn and somewhat of a loner after that.
I have an older sister who was enabled by my parents well into her 50's .It carried over to her children using my parents,also.
I went out of my way to become the opposite of that.I think that's what Lee has tried to do . Always trying to please,while maintaining some independence and distance.
Leaving Lee out of such a huge family event ,as the pregnancy and birth is probably painful for him. It's a reminder of all the times he felt left out or put aside.
JMO