This particular style has been heavily trained by ai so if it were it 100% not surprise me. Both google and Yandex show no direct results for the work, so I'm leaning that it is prompt gen.
You'd be surprised, what I can tell from the work is.. there are some incoherent boot tops from the kid on the left, that weird attempt at making a hand guard on the sword with some ms paint edit, that particular kids other arm abruptly stopping and the lower step fading into the wall. There's other minor things with the knights armor being inconsistent but it does look very clean at first glance.
Also when I attempted to try to find a source for the work I found the particular pic with the caption being posted by bots, so that's another tell.
But the hand guard was the only thing that stood out to me, the rest could be just how the drawing is. But like, the knights armor looks right, the window/wall is there and look good with the vines growing on it, the boots, outfits and shadows of the kids is realistic enough, AI struggles to make realistic looking anything so I struggle to believe this was AI generated