This morning my son (11) and I did this warm-up: https://www.fitnessblender.com/videos/warm-up-workout-routine-cardio-warm-up-exercises
and then moved on to one of my all-time favourites: https://www.fitnessblender.com/videos/better-posture-workout-exercises-to-improve-posture-and-prevent-hunched-shoulders
I love that last workout. During the stretches my son asked me "how do you reach that far?" (I can barely touch the ground with my fingertips when doing a toe touch). It made me realise I had come a long way. Before starting yoga and working out, I came about 2/3 down to my lower legs and that was a real stretch. Now, even after leg day, I can touch the floor.
We made it through both, him with a lot of "ooh!!" and "ouch", but he did it. And I am sure, that if we keep this up, he will make great improvement as well.