Hello Cynthia.
I certainly empathize with you and with your husband.
Our 10 month old girl has recently been diagnosed with COMA and amongst the countless other anxieties that run through you after you hear the diagnosis....I too felt overwhelming responsibility for "doing" this to our little girl, Reed.
She is our third child and as a result I have often looked back, through the details of each pregnancy I have had to see if I might see what I might have done differently, to have caused this, in my pregnancy with Reed. Really...there is nothing. My other 2 children do not have any signs of COMA...or any disorder.
To that end, I remind myself of the many factors and variables that may be involved in a condition such as COMA. There are environmental factors....our water, air, soil, food etc. etc. is forever changing.
There are those that theorize that this is genetic.
I think, Cynthia, that you should really ease up on yourself and look at how loving, caring and totally dedicated you are to your son's well being. That is what is most important for him now.
You sound so devoted to him....he will benefit from all of that positive love and care.
Chin up Cynthia.

...Rachelle