I just want to tell you my story and hopefully it will give you some hope. In 2012 I was diagnosed with severe aplastic anemia. I also was not able to get a bone marrow transplant, so I also was given ATG and cyclosporine. By 2014 I was recovering so well that they weaned me off of the cyclosporine, and today I have been completely off any kind of medication for 5+ years. God is good, and hopefully your son will recover in a similar fashion and get to live a normal life. Praying for you and your family.