Their lives most likely peaked already and they know everything is going to get worse later, so if you really love and care about the child you tell to go away and bully alongside your older children you actually spend time with, then you should let them go. What is the point of growing up as a joke and continuing to be a joke? Living out of spite gets tiring when literally everyone is rooting for you to fail.
You most likely did not want a(nother) child, and that should be no one’s problem. Not yours, and most importantly not the child’s. The child also shouldn’t be tossed in a cruel game of hot potato for the rest of their life where more people abuse and bully them for fun. If everyone wants the kid gone including the kid themselves then what is the issue? Life only gets better for people who are loved and wanted.
What classifies as wanting to die? Would you be in favour of instant death the moment anyone has the thought “fuck I wanna die”? If not where do you draw the line. What exactly does a person need to do, what protections are in place against misuse of the system. How long does a person need to want to die before it’s considered valid? Should people in exceptional circumstances be permitted, such as children who have been raped or gone through other trauma.
I find the “messiness” of reality to be logistically incompatible with such an idea