They are giving out their phone number to people they met on roblox.
The child is institutionalised, their parent cannot control their behavior meaningfully and the adults at the institution are pretty negligent and she doesn’t trust them.
I have messaged like my whole family and some friends for advice but nobody is getting back to me.
Liability isn’t really an issue here. I’m pretty sure given the circumstances the staff could literally stab the child and the parents wouldn’t have much legal recourse. But you’re right that this may be serious enough for them to act, but I worry that the only way they would act would be to remove her access to the internet and her phone and therefore her entire non-professional support network.
I’m going to tell her parents if she doesn’t grasp the dangers involved or if she doesn’t want to talk about it next time I have the chance.