wow that's great. Very accomplished for a 5 year old, he was doing stuff a lot of adults would struggle with.
The comment at 1.01 made me laugh when the dad asked "Can you see", and the son says "No, I dont need to pee"
I have a 5 year old daughter who can barely ride a bike and a 1 year old son, i would love to go out riding with them one day on trails like that..