Eye on the prize

Keeping your eye on the prize. How hard it is to do this sometimes?
These days we are often told to live in the moment and be mindful. Stop thinking of the past and future but focus on the moment. Though very often we have to experience many moments to get to the end result or journey.
How hard it is especially during the difficult times to trust that we need to go through these challenging moments in order to receive the treasure at the end.
So how do we explain and help children understand this concept.
When children are sick many find it difficult to stop and surrender to the illness and allow it to happen naturally, so how do parents help them through this time?
Stay calm, distract, laugh, find some positives, spend time together, talk?
Other suggestions?