Well, TBN is relevant, and as I mentioned, under none of the various labs' schools of thought would this oil be condemned. We don't even know the starting TAN of this product. I do, however, know that the TAN and TBN didn't cross, the TBN is still more than 33% of new (in fact, probably half of new), and TBN isn't less than 1, which covers most labs' condemnation rules.
10,000 km is not a stretch, and plenty of vehicles have been specifying such an interval for years, even with basic ILSAC conventionals. As I stated, I did that with the taxis years ago, with much older oil, and the engines lasted for hundreds of thousands of kilometers.
Considering that this Honda has gone almost 300,000 kilometers, what should he really be worrying about? It hasn't sludged or spun a bearing, and if it does sometime down in the distant future, it's already provided many kilometers of service.
Should he be buying Amsoil Signature Series and change it every 5,000 km?