The plot here is actually fairly interesting (this would be an interesting romance plot regardless, not just for a gay age-gap story), a description of some sort is sort of desperately needed.
Regarding the age gap, the older man is apparently fifty, which I can only take from the cover art to mean that he aged hard, given that he looks to be roughly in his 70's. I wonder if it's just meant to make it more palatable? (Like having someone who is "older than they look" with age gaps in the other direction, meant to sooth any objections from audience members who are on the fence.)
(That's all sort of irrelevant here, at least in my book: The younger protagonist is roughly—although it's cutting it a wee bit close—at the age where I can't see any real ethical problems with hooking up with someone much older, if that's their personal preference. They are an adult and can make their own decisions, broadly speaking. But I know others feel otherwise.)
...Finally, I am tempted to add a "sci-fi" tag because AI's don't work like that. Not yet. But it sort of matches a layman's first perception of something like Siri, so maybe I should just let it be and call it artistic license...? I'm not sure.