Sorry, but the ONLY way to do this would have been to have set up the feature before it was stolen or lost:
1. setup a mobileme account (there are free ones, or the paid full feature ones)
2. once setup, enabled the find-my-device feature under that account's settings.
In the absence of having that enabled on the device, there is nothing you can do now. You should tell your dad and have him change his online account passwords immediately.