He was a college kid, presumably he can communicate by writing as evidenced by his FB page. He can text the info if he still has thumbs.
He was supposedly a pre-med student who had received mostly Ds and Fs at UMass. He was a stoner who spent his time listening to hip-hop and rap music. That is probably what the aunt meant when she said that he was American.
Recent studies have shown that heavy marijuana use before the age of 21 can cause short term memory and a decrease of 8 or 9 points in the IQ. It also increases the risk of psychosis. So maybe .
He’ll face dim job prospects once he gets out of the Massachusetts jail in 10 or 15 years. Hard to get a decent-paying position if you can’t talk.