We are scouts all the time, and this was something that was done in an un-scoutly manner.
Albeit that it didn't happen at a scouting event, this will forever change the dynamic of your program. The Wolf may become afraid of that Bear, and may stop coming to meetings and drop out of the program (this is worst case). This incident will grow legs and get around to the other parents in the pack, and they may or may not expect you and the rest of the committee to do something about it.
As the CC, it's your job to do damage control. On your level, contact the parents of both boys, and have a sit-down with the boys and the parents…yes, again, but with you there. Explain to the SCOUTS, that this type of behavior will not be tolerated in your pack, inside or outside scout meetings. List reasons (safety, bullying) …you are going to get some "lip"…stand firm. At this meeting, you can bring anyone you choose, and maybe even record it…I don't want to go too far into details, but if this incident is the start of bad behavior for this scout, then it needs to documented. Talk to the boys, with the parents listening. Let mom or dad make comments, but YOU are the one in control. Have the scouts explain to you, in their own words, why this was wrong. Kids want to be treated like older kids/young adults, this is your chance.
Once this meeting is over, and whatever the outcome, remind them that it's a no-no…and be done with it. Shake hands, say thanks, and that is that.
Some things that need to come out of this meeting…
1.) You are disappointed in the Bear, but we all make mistakes
2.) The Wolf shouldn't be scared of the Bear
3.) Those kids parents know that you have their scouts safety in mind
4.) Behavior like this will not be tolerated, as long as they are members of your pack
You may end up losing nobody, one or both…but make sure that you have spelled it all out ahead of time. If the family or families make the decision to leave, they are making a decision based on you educating them on what is expected. The Bear's behavior wasn't scout-like, he needs to hear that FROM HIS LEADERS….
Oh, and yes, take away his whittlin' chip until he can keep the promise…this incident happened outside of a meeting, but, it involved a knife…and he won't be allowed to carry one at any meetings until he can prove that he is 1.) sorry and 2.) willing to earn that right to carry a knife back. All parties should have to earn their Whittlin' Chip (this can be earned ANYTIME, per the Guide to Safe Scouting, most units coincide it with Achievment #19 in the Bear Book)….and when I say all parties, both scouts AND parents.
Use this as a learning tool…have the CM talk about it in a pack meeting. Have all of the scouts use plastic knives and how to handle them…this may seem like a dark cloud, but there is a silver-lining
The leader who thinks that you shouldn't get involved isn't wrong, but this incident is helping to define to you, your unit and most importantly, your scouts, that you are a scout ALL THE TIME….