Guess what, he's physically unable to practice. If he was grieving a recently deceased parent, would you insist he's fine?
Think like a parent for a second. Even if you have had a family member go off to a much more serious and much more demanding military commitment, can you say you've not worried about their mental health, their loneliness, their isolation from family, etc?
Certainly I want him to "snap out of it" and be successful at UT and his life but just step back and embrace the kid as your son for a minute...... You would probably hate what you're reading here about your kid.