Hi,
I hope your coping with this. I live in London but one thing I do know about universities (particularly a busy one like Manchester) is that in the first few weeks students can go a bit, erm "wild" and keep crazy hours. Even kids who used to be quiet. I'm talking from experience here!
Hopefully he has just got a bit distracted with socialising and forgotten to keep in touch with family. I trust you've emailed him, too?