Depends what your dad is going to be using it for really.
The problem with DSLR's is that they are quite bulky and heavy to carry around especially with a number of lenses on board.
If I go on a hike, I'll take a compact with a fixed lens but with the same size sensor(APS-C) as my DSLR, so the quality of pic is comparable. Much better than lugging a bag of lenses around.
Have you considered mirrorless compact system cameras (CSC) These now offer an alternative to both compact and DSLR. The best can match the quality and features of DSLR but smaller and lighter.
Then there are the bridge cameras which offer a huge zoom range.
So I would decide which type of camera system would be most suited to the job in hand, or prefered, then choose which brand to go for.
Also, more importantly, make sure it shoots in raw format. This way the image can be manipulated more easily in Lightroom/Photoshop, and without fear of degradation as with a jpeg file.