Would he work with you on discussing various paths, the things that each would require to ride out the current storm... find/create better (or least-worst) options... and be successful...?
A diagram may be helpful. Drawing doodles, cartooning, or comics may also help him look ahead, plan, and express himself on these matters.
It seems that he is at a crossroads... breakdown or breakthrough. Here's hoping for a breakthrough. You can guide him with a steady hand, but ultimately it is up to him to take ownership of his life, relationships, and education... and make things work to whatever degree possible.
I would be quite frank in saying these things to him, and I believe these would be my answer to his every grumble, mood, complaint, etc from here on out.
As an aside... considering his current level of stress, I would think that eating healthy would be of crucial importance. I would keep plenty of fresh fruits, veggies, nuts, cheese, etc on hand for quick, nutritious snacking.