I have come up against this many times, go easy on your boy!.
Unfortunately the toilet will most likely need to be removed, if it's upstairs the it will be fixed to the floorboards and quite simple to removed but if it's downstairs it will most likely be on concrete which could mean a new pan as taking it out may break it.
It could be possible to remove the pan connector and get to it that way, I have managed this too but again it depends on the fittings,I have also known people use a coat hanger but I would not recommend as it will scratch the porceilan.
If your house is quite new then that will be an advantage.
I would advise putting the job on ratedpeople with a budget of under £100 to start with.
Hope this helps.