What Is The Recovery Time From Induced Coma?

My brother was put into an induced coma Monday after his heart stopped during a procedure. They did CPR on him and he was dead for a couple of minutes. They have since stopped the coma medications and he is only opening his eyes. They are going to do a brain MRI tomorrow. How long does it take after the induced coma drugs are stopped before he is somewhat back to normal if he has no brain damage?