You can refer to him as a woman that's fine
What's not fine is to expect us to believe that they are a woman or to expect us to hand her woman's rights without significant gatekeeping, and sometimes not at all
So your friend was a nurse and I asked for a female nurse , they should not be offended if I do not at that point consider her a woman
If your friend was really good at cycling, I would not expect them to put themselves into the woman's team ( although I think a competitive sport solution should be available to her)
Many transwomen are aligned with this way of thinking and I really feel that the TRA is distracting from supporting these transwomen and providing the structural fixes and support that they need ( perhaps more closed cubicle unisex toilets for example or their own rape crisis centre )