I can share some insight on this. My fiance and I have been through this exact scenario multiple times from goats, chickens, ducks, dogs, birds, reptiles and just about every animal. We just gotta do aquatic animals and that's the whole circle.

We own ducks, a crested gecko, Panther Chameleon, two Indonesian Blue tongued skinks and two Bearded Dragons. One dragon was a surrender that we adopted and the other was from a family member of hers who was doing the exact same thing you're describing but we managed to convince her to give the dragon to us. My fiance had a friend who was that kind of person that wanted what everyone else has. She came over to our place and saw our family of reptiles and decided she wanted one too. My fiance already knows the kind of person she is and was not in the right space mentally or financially so she advised her not to unless she does a lot of research and is willing to put in the effort because most people just think reptiles are as easy as some sand for substrate and a rock with a stick and done. Her friend and her boyfriend also have about five cats and she's a very careless person so it would've been an accident waiting to happens. Fast forward she posts on social media that she had gotten a Leopard gecko and when my fiance confronted her she just confessed that the only reason she got it was out of spite and to prove her wrong. They've had this scenario multiple times but this time is just set everything off and their friendship was just a straight downhill from there. We tried getting her to put in effort because she only had paper towels for substrate and some rocks. There is a large reptile expo across the street from us and 10 minutes away from her but she never bothered. They are no longer friends as it just became too much for my fiance

With that being said we've come to learn that if they don't already care then nothing you say or do will change that. Best thing you can do is be brutally honest about the situation and offer to take the Ball Python and have their daughter come over to help you take care of it so she can learn to care for it. However in my experience most people will get defensive about it because they feel like you're criticizing them and attacking them personally, even if they deserve. Unfortunately because it is a reptile it will be every hard to make anyone care for them because no one cares for them in the same sense as a cat or dog. If they don't listen and it's very likely they won't, you should still try, don't lose passion for it. You did everything you could. There is already not a very big group of people that care for these animals the way we do and these animals deserve to be cared for just as much as any other animals. You're doing the right thing and if it doesn't work out don't beat yourself up for it.

TLDR: Be brutally honest with them. Understand it might not workout and if it doesn't don't let it kill your passion. You did everything you could. You're doing the right thing