What you want us something like this:
https://www.amazon.com/Tecsun-PL-600-Shortwave-Radio-Black/dp/B00ESUOMFW
There are cheaper ones available, but having a digital tuner is nice, so I'm linking this one. This will cover most, if not all of HF, and will do SSB. You will be able to listen to almost everything HF has to offer. Pretty much the only caveat is that SSB may not be the correct bandwidth for amateur signals, so you may get some overlap, and that CW will definitely have overlap when trying to listen in the SSB mode.
I think the controls are too small for your dad, if he struggles with his fingers, I wouldn't go for anything smaller than a Tecsun pl-600
https://www.amazon.com/gp/product/B00ESUOMFW there is this for 130 usds then there is this https://www.amazon.com/gp/product/B000NOSCN0/ for around 500 usds. i dont have that kind of money.