In all honesty, I don't know your cousin and I'm not qualified to answer that. He needs a doctor or therapist. Sadly, there's not much you can do other than not abandon him. Unless he is willing to making changes and work on himself you cannot force it on him.
His parents can take him to therapist considering, he's barely 16 so there is chance.
What exactly it needs to be done first except curing his fascism? He's extremely bigoted, literally just parrots the same stuff even when someone explains him somethig.
In all honesty, I don't know your cousin and I'm not qualified to answer that. He needs a doctor or therapist. Sadly, there's not much you can do other than not abandon him. Unless he is willing to making changes and work on himself you cannot force it on him.
His parents can take him to therapist considering, he's barely 16 so there is chance.
What exactly it needs to be done first except curing his fascism? He's extremely bigoted, literally just parrots the same stuff even when someone explains him somethig.