First I want to say God bless you and your son. My father had a transplant and lived 11 years so I have been in more waiting rooms for cardiac caths than I wish to remember. The difference was he was my father not my child.
I do need to tell you that our 3rd daughter died of a terminal birth defect nothing at all related to downs syndrome. But in our research about birth defects we found out how very many parents do not carry these children to term. You are a brave and blessed woman to mother such a special child. My admiration for parents of Down Syndrom children really grew when I found that out.
One of your previous responses sounded like they could get you into contact with other parents with similar difficulties. I know they can help you more than anyone else. I would be happy to help you any way I could. Also if your hospital has a child life specialit dept talk with one of them about contecting you with parents or other for support.
God Bless,
J.