iPhoto's quite resilient, IME. I'm not sure from your text whether they've tried restarting the machine? If they are just wary about damaging iPhoto I wouldn't be; just restart. If it refuses to restart, use Alt-Cmd-Esc and then Force Quit iPhoto then restart the machine.
Or have they considered changing their password back to what it was before?
If they would like me to do a remote session then that might be possible.