Johnny,
I'm not sure if your parents are understanding everything the doctors are telling them correctly, or if something really strange went on.
Who is your brother's family doctor? Is he an internal medicine specialist or just an MD or DO? He needs to be evaluated by an internist right away, and referred to to appropriate specialist. If someone's heart stops, there is a reason, and it must be dealt with. When the body stops growing (around your brother's age), there are a host of problems that can reveal themselves. None of which should be ignored. There are several "milestone" ages in human development and aging during which problems usually manifest. I'm sure if you think about it, you realize that.
Unfortunately, the philosophy of most hospitals in regards to patients admitted through the ER is "stabilize and release". The concept of finding out what is actually wrong is no longer a priority.
Talk to your parents and your brother. If they are not entirely sure what happened, and are not comfortable with the outcome, it is imperative that you convince them to take your brother to an internist immediately.