The antidepressants were prescribed by a psychiatrist when my DC was under CAMHS. From 18, the GP took over the medication reviews. This is pretty standard. DC doesn't want to have any counselling or therapy.
I presume you're aware that even under 16, a young person can have the right to make choices about things like therapy, if they are deemed to have capacity.
Over 16, it is assumed the young person has capacity unless there is proof otherwise.
So it doesn't matter if you'd not be happy with it, if the young person doesn't want treatment, it can't be forced.
Or do you think a non-binary gender identity would be reason enough for them to be detained under the Mental Health Act? Do you have any experience of the facilities that treat young people who are detained?
And tbh, my experience of the NHS largely seems to be affirming of trans identities, so I'm not sure, even if they were forcibly taken away for treatment, that the outcome would result in my DC being cured of gender dysphoria.
It's simple for me; my DC's mental health and happiness has noticeable improved. More engagement in activities. I know if I refused to affirm, their well-being would decline. And that's sufficient for me to accept my DC has a non-binary gender identity.
I have been told on this thread that I'm feeling things that I'm not; I'm angry, distressed, hostile. I don't expect anyone to understand why my DC feels the way they do, and I'm not here to try and change anyone’s mind. I've just given an honest account of our situation and refuting the position that all NBs are attention-seeking narcissists.