Wow! I can only imagine how hard this is for you and the family. Being a mom of a 12 year old boy, I dont even really even know what to say...
I had venous TOS and had rib resection surgery (6 months ago in Denver) that went very well. I have not heard of Dr. Freischlag, but it sounds like your son is in good hands. Youth will probably play a big part in this, kids heal so quickly!
Please know that you, your son and the rest of your family will be in our thoughts and prayers.