I’m so sorry, sending love your way. People can change, and it may take you moving on from them and finding more loving and supportive community for that time happen, but it’s not something you can/should be expected to force. You deserve supportive people in your life! They’re out there and ready to accept you with open arms ❤️
Hopefully they grow as a person and change in time.
Growing up in a fundamentalist Christian extremist family, it can be hard to rewrite one's own objective moral code. It takes time and reflection to develop philosophically and emotionally independent of the socially isolated projected/pressured rigid stances that may have gone unquestioned since birth. It took me years of atheism to really take control of my own moral compass independent of any peer pressure and I'm sure I still have room to grow.
I don't mean to project myself onto your friend. I just wanted to say, with some substance: Much love! People can change!
I feel your pain. May you find 10 more friends just as close as the one you lost; who are not transphobic.
Or maybe someday you'll have luck in educating the one you lost. Whatever the outcome; know that you are valid and accepted. Some people just haven't caught up yet.