What does the young man think?
It sounds to me like your focus is where it should be - on helping the boys grow and develop into good young men. But how are the boys responding? Is the kid in question responding well, is he still acting up or is he changing for the better? If your actions are helping him to get better, then it sounds like the problem is just with the mom. If the kid hasn't changed his behavior for the better, then you might want to re-evaluate your methods - but not because the mom is complaining. It may be that she is seeing his reaction to your discipline as being counterproductive, but she may not be expressing her concerns as well. Remember Kipling:
From what you've written here, it sounds like you are acting appropriately, especially since the committee is backing you on this. But just make sure you are getting the results you want.
I am a Cub Scout leader.
If the guy can't, let him fail. As a Cub Scout Leader I believe Boy Scouts is the time to let them, lead, fail and learn.
Hold him to the Scout Law. If he is too busy to take the the time, he does not want it. You may be the first real wall he hits. This may actually teach him you can't talk your way through things.
A grade is a grade in school. A project takes real time and work. Better to learn it before college.
I use the Scout Law when ever I discipline the boys. My discipline is to ask the boys how what they are doing follows the Scout Law. I'm sure the boy in question is failing at "Trustworthy, Loyal" The parents are pushing you to break "Obedient".
Hey, bringing in new and relevant info -- cool.
I have found the Scout Law and oath fairly solid. We can argue interpretations on a few points. That understood, most actual points where you have to step up and discipline / regulate the boys it works well.
The Scout Law for those who might not remember / know.