Buy a set of keys of your own, then just unplug your dad's and use your butcherized version... there are many other non critical parts to a computer that can also be destroyed in the name of fun, without damaging the actual workings... I think they should put lcd screens on the main cabinet with a face on there, responsive to verbal abuse, so you can "frighten" your machine by shouting at it, and have it react and say "sorry master, I'm doing the best I can..."
Actually that could be just a little background program in db, you could simply record input and measure volume, if it goes over a certain threshold the face pops up and apologizes, then you have the option of tearing it's face off, or strenly admonishing it to be more careful in future...
ZX Spectrum 48k Issue 3, Radio shack Tape drive, Rank arena 12" T.V. set.