Writer’s dilemma: Critiquing a family member’s AI-generated novel

To make a long story short: My stepfather-in-law was laid off in January. My husband and I both begrudgingly tolerate the man. His ego and quirks make him difficult to be around, but fortunately, we only have to see him once or twice a year (they live five hours away) on our obligatory visits to visit my mother-in-law. Here’s the kicker. On month eight of unemployment, he decided to start what I can only comfortably describe as a poor attempt at AI-enabled grifting. He started by generating Toby Keith-esque country songs and posting full-length “albums” on Facebook. My husband and I rolled our eyes, thinking it was just a “local boomer discovers AI” sort of situation. He’s since piloted a LinkedIn-style leadership motivation series of AI-generated texts and images, the pairs of which almost never make sense. Again, we mostly ignored it. But then, the books started. Which meant I was dragged into it. For a little extra color — I’m a career journalist turned specialized corporate content writer/strategist by day. By night (mostly early mornings, actually), I write novels. I’ve spent the last six years working daily on a series that means the world to me, and I’m currently in the trenches of my seventh round of edits on the first book, with the full intention of querying my best work (I got so close in the last round, but my word count sank that ship - lesson learned!). I take this hobby as seriously as I take my daytime career. I am no master of this craft. It’s a day-in and day-out process to become 1% better at storytelling every time I sit down to write or edit. So when my father-in-law unceremoniously sent me his AI-generated manuscript wanting to “get my thoughts,” I was torn. Of course, in nearly any other situation, I’d be more than happy to review a friend or family member’s writing. I do it all the time! But this felt different. He’s fully intent on self-publishing this novel. Do I think it’ll sell? No. I don’t! I can’t say I feel “threatened” by another writer, or that I’m worried this book is going to be a runaway Amazon success. I read it. It’s… fine. The prose isn’t egregious because the AI was decently well-prompted. The characters have no arc. The plot barely moves. It’s 90% atmosphere, 5% police procedural tropes, and 5% repeated descriptions that are immediate AI red flags to a semi-trained eye. My mother-in-law has urged me to “please be nice” about the whole thing. She knows that even though I work for a company that plays in the AI space (we’re healthcare-adjacent), I have strong convictions about the use of gen-AI for creative work, especially when someone is trying to pass off the work as their own. We’re visiting in a few weeks, and they “can’t wait to talk to me” about this. Writer to… writer. I guess. My question for you all: What do I owe him in this inevitable conversation? Has anyone else encountered a situation where they’ve been asked to review/critique someone’s AI-generated work? I feel icky even having read it, but I really struggle pushing back on this guy. He’s exhausting to be around as-is, and I’d prefer to keep things as light as possible, just to get through the trip.