Okay, for starters, no one style or running method will fit anyone. And someone that is going to so blatantly ignore that fact to tell someone else that they will "eventually educate" them needs to take a second and breath. You've already educated him on your opinion. For every runner, something different works. That's why we run barefoot, right? It works for us. I really hate when people preach to me something that is mostly their opinion, but they preach it as an absolute truth. For example, I cannot stand barefoot runners who try to convert everyone to barefoot running. Sure, it has helped me, but I do not recommend it to anyone. I simply tell them the benefits I have noticed from it as well as the downsides and let them decide if it is something they want to try. Maybe that's why I've switched to barefoot running without reading a book, article, or anything else about "form". For 3 years I had a coach tell me what to do and not to do when I ran cross country. It took me over 10 years to figure out that things he taught me did not work for me and were, in some cases, incorrect. (Now to turn this back on topic) For example:
He always told us to keep running. If we stopped, we might as well not start running again because we killed our workout. That is sooooo not true. Hell, that has helped me get faster on longer runs. I will stop and walk a few seconds and drink some water. I actually want to focus on recovery. I am working on doing that during my runs so that I can cycle between high effort and periods of lower effort to recover. Perhaps if you are having significantly slower mile times throughout your 5K, you can practice doing this. Run 1/2 mile at your normal pace, then just slow it way down for 30-60 seconds. Then back to your normal pace for another half mile and so on. Like I said, it's worked for me, but you aren't me so it might not work for you as well.