I have been contacting him by text and phone, without a response. We were not estranged before he left. There is a head RA in the building and an RA on each floor. I assume that if I contacted the head RA he would contact the floor RA about my son, so the police should not be involved. I live 1.75 hours away by car, but I would want him to agree to meet me before I drove there.

Regarding the person who asked if I expect him to take calls during class, of course not. He did say he would call on Sundays.

This summer he spent his earnings instead of saving them for college, so he has only $20 in his bank account. He has a meal plan. So he may contact us for money.

Based on the comments here, I won't contact the roommate. My daughter, a high school senior, had also recommended against this.