He didn't mention specific worries like your daughter, but he was uncontrollably sad.
He no longer wanted to do anything that he previously liked. He wouldn't even play video games anymore. Instead, he'd sit and cry.
Going to school pretty much stopped. Even if I could get him into the school, he'd end up coming home after banging his head into a wall or getting stuck between classes when he suddenly couldn't go on anymore. He spent a lot of the time with a school counselor.

We went to Maui for a week at the end of November. We hoped that would reset him. It didn't.
We hoped winter break would help too. It didn't.
This semester started this week and he now has a stripped down schedule of only 4 classes. He's had a couple of doctor visits regarding it and was recently prescribed Prozac. It seems to have helped.