Uh huh. He was uncomfortable in the men's, realised him being in the women's would make women (who had no other options unlike him) uncomfortable, and decided that his discomfort was more important than the discomfort of an uncounted number of women. As I said, very male coded behaviour. He matters more than the women whose space it is and have no safer option to decamp to. And again, no women confronting him absolutely doesn't mean they didn't mind. Women rarely confront unknown men.
There was no evidence at all that transwomen are at risk in men's toilets. Fionne Orlander has said that the most that happens is a man will see Fionne and double check the sign on the door. Fionne will confirm it's the men's and that he's aman, and everyone will go about their day.
Here's Fionne looking lovely and clearly safe in a mens toilet:
https://www.change.org/p/boris-johnson-a-plea-for-third-spaces-for-transgender-men-and-women
And here's Kathleen Root in his 1000th photo of himself safe in a men's toilet:
https://x.com/RocknRoller2019/status/1920553022347730977
Your friend will be just as safe as any other man in the men's.