Isn't (wasn't) the idea behind organized sports like Little League/Pop Warner/whatever the kids hockey is called to match kids of roughly equal age and talent? At least until the parents and the commercial sponsors got into it.
The kid's a year older than the rest of the players. At this stage, a year means significant physical development. Letting him play in the 11-12 year old division would be like bringing a Japanese pro baseball player into MLB - significantly outclassing everybody else.
What's wrong with this countryt is that there are too many people wanting special consideration. The kid's dad says developmentally he was “a full five years behind the 12-year-olds in the majors” because he's been playing lacrosse instead of baseball for the last five years. Dad wants a break because his kid has not got experience playing baseball like all the other kids have. Little League is not like golf or bowling where you get a "handicap" score to even you up against more experienced, more talented players.
No sympathy from this corner.
stay safe.