I think some sort of intervention was definitely needed, if no one had stepped up and the child had ended up with serious health problems everyone would be asking why the hell no one did anything. I do think allowing a child to get that size is neglectful, whether it was out of love or not, they are clearly in denial about their own size and need help before they ruin that poor boy. You don't get to 15 stone, at age 11, just from buying sweets on your way home from school and having the odd unhealthy school dinner. He obviously isn't eating right at home or getting enough exercise.
Saying that I do think it was a complete waste of police time, as if the police force isn't stretched enough. Social services should be dealing with things like that.