What does the boy was mending the health of a crack in the sitting room floor with it?

The phrase suggests that the boy is using a material, likely a patch or adhesive, to repair a crack in the sitting room floor. This act of mending implies a sense of care for his environment and possibly a desire to restore order or beauty to the space. It may also symbolize innocence and the small ways children engage with their surroundings, taking on responsibilities in their own way.