While that list of drugs is extremely concerning, I will play devil's advocate real quick. Amphetamine in the most positive term could have meant he was abusing Adderral without a script.
I in no way condone that, but thousands of students at every college in the nation abuse that drug for testing or recreational purposes on a consistent basis.
Hopefully he can get the help he needs. He will probably play the rest of his days overseas. Very sad to see.