Alcohol is my guess too - callit an educated guess.
Assuming in all that follows that this is the case: This kid, according to biographical material, was under an obsessive level oressure (parental pressure form early adolescence on that he internalized) to perform. The pattern was set early.
From there, there are other components to the picture but simply put, relief from the abnormal inhibitions of this kind of pressure found relief in the anti-inhibition effects of alcohol.
Pray for this young man - in any case.
I've seen more tthan one recovering alcoholic turn it around, get past their crisis point, and emerge stronger, deeper, more compassionate, and more complete and effective human beings.
Alcoholism of this sort is a mindset moreso than a physical addiction. Sobriety is a shift in worldview.
When he is freed to play high level football because he
wants to instead of becoause he
has to, he could still become whatever he was capable of - and more - as a quarterback.