I can't tell you a lot about the city of SF itself, except that it is a very expensive place to live and parking and traffic are very difficult! Getting around the city can take some time, I suggest getting a place near his school.
Sf is divided into districts, each with their own personality. These links give a short description of each district.
http://www.sfgate.com/traveler/guide/sf/neighborhoods/
http://www.san-francisco-real-estate-agents.com/Castro.html
Stay out of Tenderloin and Hunter's Point!!!
For rentals try http://www.craigslist.org
If there is anything else you need to know, I will try to answer