Hi woofy! I see you're from my home state.
All villagers (at least in VV1 & VV2) CAN heal other villagers. That includes children.
However, just because they're CAPABLE of healing, that DOESN'T necessarily mean they WILL heal.
In VV2, using children to heal is a good way to get a jump start on building skills. If a child is used often enough, it will be a "apprentice doctor" until it turns 14 when it will automatically become a trainee doctor. In fact if a child is used frequently, it may even become an adept doctor on it's 14th birthday!
