@agedman you seem to think that there is truth to transgenderism. That someone can actually alter their gender. They can't. They can only alter appearances. They are still male with an x and y chromosome. If they continue to live as a woman they are continuing in their sin willfully.
The opening chapters of Romans clearly teaches that the twisting of the mind is a sign that God has given not just that person, but the social order of that society, for example the U.S., turned over to destruction.
So, certainly, it is well understood that some do consider themselves what they are biologically not. That does not mean redemption cannot take place.
However, as the OP relates concerning this person, they have come to understand the sinfulness of the altering done.
I have not spent time in my responses concerning the medical issues. Perhaps because you do bring it up I should make a bit of a remark.
It is a popular myth that restorative surgery can be done.
It cannot (unlike other sin) undo that alteration that has been done. Bluntly, that which is removed cannot be replaced.
At best the modern restorative surgeries (more often performed upon the wounded vets) are a pitiful, painful, ongoing medical ordeal.
Unlike a vet, this procedure in which the person has so completely been deformed and formed into that which they now are, has significant potential of leaving the person with no longer control over the basics of discharge.
In essence, it is better that nothing physical be done.
Setting that aside, the birth "gender issue" really isn't an issue. The Scriptures Christ saying:
"For there are eunuchs who have been so from birth, and there are eunuchs who have been made eunuchs by men, and there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven. Let the one who is able to receive this receive it.”
Accordingly, the OP presents that the person has been made a eunuch by both men and by determination of the mind. They will live their life as a-sexual as can be lived.
That only leaves one issue. That concerning their outward appearance.
(Imo) in order to NOT to allow the devil to bring confusion to the assembly and the workplace the person may for a time continue in the manner of clothing choice folks are accustomed.
Now, that may not be ultimately agreeable. But there is NO sin involved as some on the thread want to assign. If one has no sex, then what one wares is no body else's business. That person is free to dress in the manner that pleases, as long as it is modest.
This is why it is important that time, maturity in Christ, and reliance upon His preservation and authority be granted.
No doubt, should that person grow in the Lord,
they will one day stand before the congregation and bring glory to God for the leading He has given.
That person will then stand (
with the authority of the congregation) in the work place and again bring glory to God in testimony to the heathens of Him who loved first, shown light first, provided the strength and courage in the faith first, and that such is available to any who desire under the authority of the work of the Holy Spirit to have their own life transformed, not as a matter of reformation, but a mater of transformation that ultimately results in reformation.
DNA means very little to the creator, it is for propagation in the flesh of this world and does not pertain to redemption nor to eternity. The new creation has no gender specifics.
This person, according to the OP has determined not to live as a woman.
Time and growth in Christ will change the outward appearance.