Thanks for the suggestions but, only the very simplest solution will work. This person hardly knows how to turn his computer and off, so it would be impossible to explain to him by phone how to do any of this. We need the simplest possible 'plug and play' option. His 20 year old daughter has refused to even discuss it with him as she knows it will end in tears!
I think downloading FF onto a stick and posting it is the best option.