Ashley from Make It and Love It shares a free pattern for making a child-sized Balaclava – that’s a fancy word for a ski mask hat. The fleece hat covers the head and neck and most of the face, with an opening for the eyes. The opening is stretchy, so if the full face cover starts to bother him he can pull it down under his chin. The pattern she gives made a Balaclava to fit her 5 year old son. Go to Make It and Love It for the pattern and tutorial.
[photo from Make It and Love It]