* (Currently) Most AI generated images have an aesthetic to them, so it's easy to spot sometimes. Typically low-res, smeared details, bad hands/body horror. This may improve over time, but I don't know how I'd feel ethically (both morally and in work/effort) leaning so hard on AI.
* For me at least, as soon as I learn something creative is completely (or mostly) AI generated I lose all interest in engaging with the content beyond surface-level consumption. I think fundamentally AI generated creative works are banal and will age horribly over time.
Honestly I think it would be much better to buy a nice paperback kid's book made by a human as a gift for your friend's kid. They'll love it and the kid will have a connection with a human author and artist.