This just came up in my life. My 11 year old son asked that I take him to confession because he feared he may have committed a mortal sin. I readily agreed to do so - he is a great kid, and I was glad that he was attentive to his own conscience, and I told him so. I also told him I would not ask what the issue was, and we settled on a day that week to attend. I did tell him that it was doubtful that he had committed a mortal sin at his age because he was not yet of an age in which he could have full consent of the will. Maybe a little too deep for an 11 year old, but I wanted to ease his mind.
I later questioned myself about it, and wondered if he did not need more counsel from me than I had provided, as I had not asked him anything about the act that was bothering his conscience, and I did so purposely at the time, wishing to respect his confessional privacy. So I went back to him the next day and told him that I was not going to ask him about what he planned to confess, but that if he had anything he wished to discuss with me about whatever was bothering him, then I would be happy to talk with him.
We did go over the issue, and I was able to ease his mind.
I agree that the seal of confession need not inhibit a healthy discussion of right and wrong, even after the fact (i.e., after the wrong is committed). In my case, I reconsidered because of his age, and my doubt that he was yet capable of knowing what was a true mortal sin. However, at any age, I would not think that a past or potential confession should be an absolute barrier to a discussion of the issue. It is all about avoiding sin, and we could all use all of the help we can get.