Names and pronouns interest me a lot - my son is demanding that I use his new "feminine" name (I find that very difficult indeed but am prepared to use it in some circumstances) and she/her when talking about him. I refuse to change my pronouns that I use to refer to him, for various reasons.
Firstly, they are my pronouns, not his (or "hers"). They are my words with which I try to communicate my thoughts. I strongly object to controlled speech, especially when it comes with a threat, the threat of estrangement if I refuse to have my language coerced.
Secondly, the cognitive dissonance of calling my son "she" is enormous and very painful. It is unthinkable for me to deny that I have a son. I have loved my son since the moment of his birth. He is not my daughter. And trying to communicate while constantly policing my pronouns ends up with me being incoherent. and distressed.
Thirdly, I don't think it's in his best interests to feed his muddled thinking about sex and gender. He can wear a dress if he wants - he's adult and able to make such decisions. But he seems to be mixed up about the implications of liking stereotypically "feminine" things. Feeling more in line with "feminine" values does not make him any less of a man; finding some of the societal expectations placed on men uncomfortable does not make him a woman. And he is naive about the impact of cross sex hormones; he appears to think that feminising his body will make him more comfortable with his gentle nature, and also that any doctor prescribing oestrogen will be completely clear about any side effects. If he uses cross-sex hormones and that doesn't sort out his confusion over his "gender", what's next? Breast implants? Castration and penile inversion to produce a non-functioning mockery of a vagina, with complete loss of fertility and normal sexual function? Lifelong self-inflicted medical problems.
Fourthly, I am not prepared to deliberately and repeatedly lie in order to make other people, especially my son, comfortable.
When it comes down to it, the language we use matters. It reinforces or questions the assumptions of people who hear it. I believe my duty to my son is to be honest with him, in as gentle a way as I can. Activists tell him that I am being hateful and unloving. I can only hope that at some point he remembers that his family, while imperfect, have always loved him and done our best for him. In the meantime, we are estranged and saddened, because society has told us we must accept nonsense as reality and be kind at the expense of truth.