There are lots of adapters for Nikon lenses on Canon cameras.
With all of them, you'll get infinity focus, due to the fact that Canon's lens registration is shorter than Nikon's.
What you'll forgo is autofocus and auto-stopdown during exposure. You will have to meter by stopping down, setting the exposure, opening up to focus, and then stopping down just before taking to shot.
With some Nikon DSLRs, basically from the D7000 and up, you can mount these lenses and the body will meter. You can use A and M modes. On cheaper models, you can mount the lens, but you will not get metering. You will however get auto stopdown when taking the shot.
There are some caveats though with lens compatibility. I'd use Roland Vink's Nikon serial number database to identify the lens mount variant on your dad's lenses. Anything newer than "AI" will mount fine on the D7000.
To add to the confusion, the Nikon->Canon lens adapter will not have any compatibility issues with different lens mount variants.