@MusicMakesItAllBetter I'm sorry for your friend because I'm sure all of this makes it difficult for them. To answer your question, your friend is a man - albeit one who has chosen to live as a woman. And that's perfectly OK.
The cynical side of me wonders how well they really do pass if they went through male puberty, but I'll take your word for saying that they do. It's very few transwomen who genuinely pass as a woman in real life - photos can be quite deceiving, but in real life there's usually a few clues.
I think it's difficult for people who have close friends who are trans people. Because you accept your friend for the person that they are, including how they choose to identify, so thinking about their biological reality can cause cognitive dissonance.
I have said many times that I feel really sorry for trans people who don't take women's places, invade their spaces, or speak over us. The problem isn't people who are just trying to quietly get on with their lives - it's the majority who overstepped the mark and have been aggressively trying to erode women. Trans women like India bloody Willoughby insisting that they ARE biological women and that there's no difference between them and actual women.
The group that have pushed women too far are to blame for the current situation. I think at the start most women were happy to turn a blind eye. But the push, push, push at our rights, and the constant attacks on women's rights has peaked many of us.
The other problem is that there's quite a lot of groups under the trans umbrella. It's no longer just the small group with gender dysphoria - there's also those who get a sexual kick out of it, such as AGPs. And then of course there's a large group of predators who disproportionately claim a trans identity.
Image attached showing the much greater number of sexual offenders in the trans community - numbers from HM Prison.
We know there are lots of perfectly nice, lovely people with a trans identity. The trouble is, there's plenty who aren't - and there are some who actively want to harm women.