We don't have enough information to tell you what you need.
You need to know the mount of your camera, and the mount of the lens.
We know your camera has a Canon EF mount.
But what we don't know is what your lens mounts are. Pentax lenses are available in a couple of different mounts, and that info doesn't tell us what it is.
Sigma lenses are third-party lenses that could be available in any one of many numerous different mounts (although if your dad used them all on the same camera, they are very likely the same mount as the Pentax).
So once you learn exactly what kind of mount the lens is, then you'll need to search for a "X to Canon EF adapter"... with "X" being whatever mount is on your lens, obviously.
Be forewarned though, that depending on what your lens mount is, it may or may not exist. Not all lenses can be adapted/mounted to Canon EF with a simple click-in adapter. Many can't.
And of course even if they do fit they will function purely as a manual lens, obviously, and the camera will have to operate in full manual mode... there will be no camera control for focus, iris, nor any image stabilization.
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