It sounds like his dad never tried Google, thus there was nothing to "stick".

I think the lesson here is that while the search engine switching cost is $0, people are creatures of habit and may continue using something long past its expiration date if it is returning expected results.

What we see from this case is also why IE has such a huge market share. Less computer literate people will start using whatever some more experienced entity tells them to, and will keep using it until/unless they are forcibly switched to a new platform.