no yanbu. Surely any parent should realize that when they buy a pet for their child the child will ultimately get bored of it and it is the parent who will end up looking after it.
We have lots of animals (dogs, cats, birds, rabbit) but although some of them (budgie/rabbit) are ds's, the only reason I allowed him to have them was because I am a huge animal lover and have no issue with being the one left to look after them. I was the one who spent hours with the budgie getting it tame enough for ds to be able to let out, i am the one who goes out in the rain to feed/clean the rabbit. If I wasn't prepared to do that then we wouldn't have the animals. And if I'm honest we have the animals as much for me as for ds .
I do think that having animals taches children some responsibility. I also don't think that animals should be considered throw away items that you can get rid of when you've had enough. When my first guide dog retired there obviously was no question that I would keep her as I couldn't bear to part with her. But also one very important factor for me was that I didn't want ds growing up thinking that when a dog gets old you can just get rid of it and get a new one.
Also whoever said that there are lots of charities who will take on unwanted animals, that's not always the case. A work colleague of my mum's was looking to rehome her rabbit and none of the rehoming charities were able to take him on because they are inundated with them. Rabbits are the most popular pets in the UK and are also the pet that is most abandoned as people take them on and really don't realize the amount of work they involve (cleaning cage every day for instance).
Scorpio tbh I would be inclined to either have a harsh word with your friend, or a word in the ear of the seller. Yes maybe it's your friend's mistake to make, but this is a question of animal welfare, and is it really fair that an animal potentially has to suffer in order for your friend to learn from the situation?