In the pic he posted I could not see the lighting on the top of the cage... If she does not have the proper UVB she will develop MBD this in turn will cause major issues when it comes time for her to lay eggs. Females lay infertile eggs. She will also need a lay bin as a permanent fixture in her cage. They also should adjust the vines and add proper plants. Succulents are not recommended with chams and veileds will try to eat their plants. I bring it up because chameleons are more of a specialty reptile. Most people unless they are in the hobby and active do not know proper husbandry for them. So people get incorrect info quite often.
You can give your parents this site to read about proper husbandry.
https://chameleonacademy.com/chameleon-husbandry-program-getting-started-with-chameleons/
And refer them to the forum for any questions they may have. We would be happy to help them.
Should you see the tail change in any way go ahead and post an updated pic here. I would be happy to take a look.