Kids need to understand how to be able to accomplish to the limit of their ability for themselves, their family and profession. To do that they need to have the knowledge & self-control to stay healthy in all ways, in spite of peer pressures today.
Kids also need to understand how to deal with loss as it is a part of life and that is difficult to comprehend when young. Maybe it can be stated in a positive light, "Now we both know we have a limited time together, we can focus on important things so you can get the most out of your life."
Helping a child to accomplish something significant really does stick with kids. Steve Jobs told how much he appreciated what he learned from his step-dad in understanding how to build things and why they had to be done "right." Each kid is different.