Can a man who is looking for a sex change be with a woman during the prerequisite stage?

Patient: Hello, im a girl from Ontario, and I have a problem. Well, sort of. My two best friends are madly inlove with each other, but the guy of the relationship wants to go get a sex change, since he can’t stand being a guy, but they want to be together and she’s alright with it, but we have all heard that apperently if he wants to even get a chance at it, not only does he have to live as a woman for 1-2 years, but must be single or be in a relationship with a male to technically “prove” he is a she…can you please tell me if it’s true or not?