Honestly I don't think we need to teach children too technically about Bitcoin as they are young and they should enjoy their childhood as most as possible. Don't put them into pressure of learning Bitcoin too early. They have many years ahead to learn from education to Bitcoin.
They will not yet capable to understand technical bitcoin their mind still on playing. Just give them a portion to enjoy their childhood but it is a good decision to introduce them just to know the name of bitcoin, what its look like, to keep them stay close with bitcoin.
In this case of the boy, I remembered one thing that the children will be developed in the same way as the parents raise their children from childhood. The boy's father may want to expose his son to Bitcoin from an early age.
Their parents have important role in growth of the children, what is thought by their parents will be followed by the children. That boy is lucky enough to have father who bitcoin users because the boy will have a "teacher" to guide him to learn bitcoin after he has enough capability to process the knowledge about bitcoin in whole.