Both grandma and Aiden are doing fine, and their livers should regenerate in a matter of months. Doctors reuse the blood that is lost. Basically recycling it so that no new blood is needed. They also give a drug that boosts the production of red blood cells so that blood is replaced by the body quicker than normal. It's a technique that can be used in many surgeries that involve transfusion and will help many more people than just Jehovah's Witnesses avoid transfusion.
Children have less blood in circulation simply because they're smaller.
Doctors have to make sure they lose as little as possible because they can't afford to lose as much as an adult. This is not the first time that a Jehovah's Witness has refused medical treatment. It's a common ethical dilemma. And a theme that has become the subject of prime-time drama in television shows like ABC's The Practice . In that scenario, the woman in the show recovered from her accident before the issue of a transfusion became critical.