Yes, sounds like this could be a wise move. My dad (now 95, living alone in his 3-storey house since mum died around 7 years ago) had one installed a few years back, and although he doesn't always use it, it's invaluable for the times/days when he's feeling that bit less mobile. Without it, he couldn't have stayed in the house -- and leaving it is almost unthinkable. (Sure, some day there may be no choice. But it has unquestionably given him additional years of independence and stability in his own home.)
Just in case, I mean it's obvious that his Dad doesn't need it, but maybe one day he will ;).