Thanks for the replies. To clarify and respond to suggestions:
1) The mileage is not an issue, He has been at the same mileage for 3 years.
2) Not increasing the mileage is not an issue either. Yes, you need to change the stimulus to improve, but we would be thrilled at this point with zero improvement, i.e. if he could just get back to where he used to be. We would love to see him run even 8:55 within 10 seconds of his PR, but he is instead running 9:20! This is not a stuck on a plateau issue, it is a falling off a cliff issue.
3) As far as caring goes, I care about all my athletes as long as they are trying. I am trying to solve this issue because I want to help this poor kid get back on track. That it will help my xc team in the Fall is just a secondary consideration.
4) He is doing great in school and socially and is generally happy and upbeat, but as you can imagine very frustrated with this massive decline in performance.
5) As far as workouts go, there has been no change really since his great freshman year and what he was doing in high school. Basically mileage, long runs and tempos during base phase. During racing phase one workout per week and one tempo or one race.
6) He has races all distances from 800 through 8K XC and his performance is terrible in all. We are already varying race distances with no effect.
7) He does not have mono. He does not have Lyme. Interestingly he does not feel "tired" in normal daily activities. Even doing easy distance he feels fine.
8) Any time he tries to do tempos or workouts or races feels terrible (nd looks terrible, I can see he is struggling. It is definitely not psychological, the problem is physical.
9) The body doesn't know what division it is running in.
10) At the end of a disastrous XC season took 2 weeks off and then only ran about 50 mpw during indoor and he got even worse. We then upped mileage to 70s and he was slightly better but still terrible and his body is clearly not responding to the stimulus of training.
11) His workouts/tempos/races in heat are especially bad. He seems like he can't do anything in the heat anymore. I know less fit and less talented and struggling athletes tend do be affected even more in the heat, but he can't do anything in the heat. I don't know if this is a clue or not?
I have seen kids perform poorly over my decades of coaching and it usually is one of 3 things:
a)50% of time it is low iron, which is fixed by iron supplementation. He does not have low iron and already takes 1 pill every other day and has excellent ferritin and hemo numbers.
b) 25% of time the athlete is doing all the work, but now with freedom and/or increased school work they are partying and/or getting too little sleep and are not recovering from the training they are doing so they get worse. This is not the case, he is breezing by with great grades, doesn't party and gets lots of sleep.
c) 25% of the time the athlete is not doing all the work. Skipping the long run, taking lots of days off, not getting it done on their own over the summer or during semester breaks. Not the case here, the kid is doing all the work.
This is why I am so frustrated, I thought I had seen it all and have never seen anything like this.
Please keep the suggestions coming/