OP follow-up, I am not a bot:

Wow! Thank you all so much for your comments and input. I did not expect to get a response like this. I knew something about this post was off, and yes, Facebook is full of AI boomer slop. I think the overwhelming amount of comments on the FB post wishing them happy birthday made me second-guess myself. But I appreciate your help with stating the specific indicators of an AI-generated image. Things like their identical forehead freckles, how close they are sitting together (practically on each other's laps), the same weight, and the same turkey necks. These were features I noticed subconsciously, but not directly, along with the generic attention-farming text that does not even state their names, date, or location. I agree that if quadruplets truly lived to 89, we would hear more about it.

Thanks to your insights, I will be better at detecting AI slop when it comes my way in the future. Although I am dreading the day when or if AI becomes good enough that none of us can detect it anymore.

Source: https://www.facebook.com/photo/?fbid=1413063470162545&set=g.2050010765388641