The issue of caring is a pertinent one for me but it led me to wonder does caring have a major place in a fictional world? What is your society like? Does it encourage caring for the vulnerable or are they hung out to dry (and this could be literal as well as metaphorical)?
Who does do the caring in your fictional world? Is caring respected or treated with contempt? Do carers get support in your world or not? If your characters are involved in caring, how does this impact on your main plot? (Of course it could be the main plot but if so what is the story behind the caring? Did the person or other sapient being of choice go into this willingly or have they had this forced on them?).
Caring can be very rewarding and also very stressful. If caring is an issue in your fiction, how can these rewards and stresses be shown? I can certainly see the answers to these making a very good deep subplot at the very least.