I don’t think allowing him to run is bad...But I’d question running a full marathon....
^ years old is too young to recognize dehydration, heat stroke, etc...
Mom: "Go ask your teacher!"
FWIW, in case you may not be aware...
Water and Gatorade stations about every mile or less.
Further, one doesn’t just get up one day and run a marathon. It requires many weeks of training to build up to that distance. Most training puts you to at least 19 miles before you’re ready. If that level of training isn’t completed, you will most likely not finish the course due to extreme pain, fatigue and possible injury.
One full marathon, dozens of half marathons and many many 5 & 10k and ten miler races run and the one marathon was enough for me, because the training is very time consuming.