DS is actually naturally athletic so in his case, it's not an thing where he should so sports to be, you know, sort of humbled. (I don't mean to sound flippant. I get it.) But I just can't commit to both chess and sports at the same time. However, he might just enjoy sports just as much. We really probably need to give it a whirl. That does factor in...
FWIW, I think if ultramarina's son were mine, I'd allow him to do the amount of chess he's asking for to the extent that its impact on other family members was acceptable, but I'd try really, really hard not to get invested in his success myself, and not to assume he'd want to do X this year because he was doing it last year - make sure the way is clear for other interests to rise up if they will.
I thought I wasn't invested, but I came to see pretty quickly how that happens. It was the coaches freaking out over him that got us invested! The second tournament, where he didn't do very well and got upset, was a good wake-up call for me. He needs to have fun doing this and we need to keep an eye on the whole thing for everyone. At this point I think I've readjusted my attitude. But, and this is important, I don't think DS has. Much has been made of him by friends, coaches, and family members (I don't mean me as much as grandparents). That has also been annoying for DD10, though some of this is just, you know, life with siblings and it happens. For these reasons, I have some interest in tamping down the whole thing.
But, see, he loves it. He's been crying about not having chess club over the summer.
