I think this style of training is fine for his event (1500m). Many runners and coaches seem to forget that there are many different ways to successfully train. I think many people get very rigid with their philosophies around training. Many people think only high milage is the way to go, others think a lot of intervals and quality work is the way to go, others do a lot of cross training, some implement all of these things. Then there is strength training, core, glute activation, recovery, etc.
I can go all day with this. My point is that the athlete and coach need to communicate and come to an understanding about how they need to train to succeed. The most important part is that the athlete believes in the training. In this sport belief seems to triumph in a lot of places, now simply believing doesn’t make someone an elite runner. However if a person has a reasonable training program that is producing good results and the athlete believes in that program that is key. I believe if more people listened to their gut and their body, they would be more successful.
Anecdotally; In college I ran 80-100mpw because it was what I was told to do. In high school I was successful running 30-50mpw. I didn’t listen to my body, I ended up in a cycle of injuries with muscle imbalances and all sorts of kinetic chain based problems. I knew better and still did it, I didn’t advocate for myself. A friend of mine did, he crafted a program that was more suited to him. With lower milage and more rest days. Of the people that came in during my year, he was the only one who had any success. I know this is an anecdote, but that will stick with me for a long time. If you know what works for you, do that. No two runners are made the same.