The Dolby atmos module is meant to receive a unique signal from a object based audio capable PreampProcessor or Receiver. It is not meant to be a stand-alone anything and is meant to create some diffuse effects, modulate the soundfield etc by working with the front and other bedlayer speakers. Klipsch implements a lower quality version of the atmos module, but anyone getting such a Klipsch hometheater speaker in the first place shouldn’t sweat it too much.
Your father-in-law could modernize himself a bit further and get a newer Sony receiver with Sony’s 360 reality spatial mapping. If he’s on a budget, here is something that can do the trick for 600 bucks (300 dollars off at the moment). You might even score huge WAF points with wife by gifting him one for Christmas!
https://www.crutchfield.com/p_158AN1000/Sony-STR-AN1000.html
Set up his previous speakers as surrounds (if he hasn’t thrown them away). 4 speakers and 2 of these built-in modules could give him an experience for music and movies that he may have never had before, if setup correctly.