Admittedly, when I first started talking to the breeder she told me that a lot of her young stock were very feisty but that she had one male who was particularly mellow and he is the one I got. Maybe I've been spoiled with an unusually relaxed dwarf, but he was happy to be handled from the very first day – and believe it or not, he was in blue at the time. I certainly wouldn't consider BP's to be advanced snakes, but for a kid who's attention to husbandry might wander occasionally (like all kids) it just seems like there are other species who are more tolerant of minor fluctuations in environment. although didn't OP say that they used to breed, etc.? If someone with that kind of experience is overseeing the situation, I can't imagine there would be any issue with a ball python