He definitely should be focused on the short sprints - I agree. But that's likely not to happen this year.
I figure this:
Despite the lack of progress, so far every year since high school he has improved in at least one event and set a PR. He's also has only been running as a 400m runner for one year. For real success, you have to give it at least two years. The first year you're learning. Its the second year that you can improve from your mistakes as you've gone through the process already. So we are in the second year of the experiment. They're not going to back out now. This year he will be a 400m runner - guaranteed. Whether he sticks with the 400m is something they will evaluate at the end of this season.
Hopefully, he continues his string of consecutive years with a PR, and improves upon his 400m time, and makes the world team at least in the relays. He turns 25 in two months. Next year it would be great to see him then step back down to the 200 and 100. Its an off year so a good time to readjust before three straight years of world championships and olympics for which he will be turning 27, 28 and 29. Kind of an ideal time for him to peak for his career.
His career is not going the way anybody would want, but it can still be turned around and so far he has yet to not make an improvement every single year in at least one event he was focused on. That has to be recognized.