^ Maybe, but humans don't always act logically, especially when it concerns something they have an emotional stake in, like playing soccer in this case. The kid would rather risk dealing with whatever negative things come about from his heart condition than deal with the pain of not being able to play the sport he loves.
@nightmare - I kind of agree with your message. Not everyone who smokes or drinks "needs" to. But as someone who doesn't do those things it can be easy to assume people have a dependency on them when you see them doing them often. It's a hard line to toe as a friend, especially when they say they aren't addicted.