It is thought that children develop empathy for others around the age of 3.
For the past two nights I've ended up sleeping in the lounge on the sofa because lying down makes me cough and cough. Yesterday morning daughter rose at 6.30am and toddled into our bedroom, stopped and asked "Where's mummy?". Husband explained that I was downstairs because of my cough.
This morning I heard daughter's footsteps in her room at 6.30am, she toddled into our room and then came downstairs. "She's coming to see me", I thought.