You are likely to ahve 50 posts - all different!
I would suggest an Olympus "mew"
Small enough to go anywhere and is splash and dustproof.
Excellent quality can be set up for just point and shoot, or Dad can experiment with a lot of settings
If mother wants recognisable easy results, take them to Boots or a sensible print shop.
If Dad having given way on the camera, he can play with digital photogaphy, but you must include good software to keep him busy.