My dad is IT/software engi. for the company texas instruments, the one who make those calculators, hes on call 24/7. But im talking about mainly hardware, he says that are people that there whole job is just to keep their servers running, and there are different people for network and such, ad you can imagine that a 10x the size company such as google has got to have a serious team of people dedicated to maintaining their servers, networks, software and such.
Lol and TI makes much more than just calculators. I'm sure you already are, but be proud of your dad because he's a smart man working for a great company!