There are some useful sub-forums here on TSR which you could have a look at to give you some ideas
-Geography and Earth Sciences
And of course the wiki section
eg. Choosing a Subject
3 Bs is a very good result at A Level and he'd have plenty of options I'm sure. I'm not sure about the foreign student part, and not really sure where to guide you but I'm sure someone else could help.
As hannahhi said though, 3 Bs at A Level is really good, it's better than I achieved and I didn't have a problem when applying. Criminology degrees usually ask for between 220 and 300 points, depending on the institution. Geography looks to be between 240 - 320 points, but having a look at the UCAS website may help him decide as well, as it'll give him an idea of what universities offer those courses, and what they're asking for.