The guy was significantly under trained until joining Hansen/Vigil.
It's a pretty simple formula -- under trained, raw, D3 guy who was 8th a NCAA XC; and ran 14:36, 29:41... put him under the tutelage of intelligent coaches... get him from random 50-60 mpw training with sporadic 70 mile weeks to consistent 80 mile weeks... stick him in a training group... get him to altitude... and get him to go all in.
The 1:08 half even being in the progression is ridiculous. His college 10k equates to sub 1:06.
It's not out of the question that the result 2 years later is 1:01:48. He already has the 10k credentials to prove out 1:01:48, he ran 28:06 last year. Seems the longer the distance the better he gets as his 5k PR is only 13:49. And the half is probably a sweet spot given his overall training volume.
Give this guy some credit. His progression is not unrealistic. Once he got serious and had some structure in his training the talent became visible. Also, altitude folks.