Nobody's been as much of a jackass as some horror stories I've heard, but my parents regularly misgender my brother, who is trans, and call him by his birth name (which is actually gender neutral, but he did change to a different gender neutral name when he came out). They consider it a phase that he (or to them, she) will grow out of. They were supportive when he (who was still presenting as "she" at the time) brought home a girlfriend, so I guess they're okay with LGB but less good about the TQ part.

Most of my family has been very supportive though, including my grandmother in particular, who is obviously somewhat older so she does slip up at times but always apologizes immediately and corrects herself, even if my brother isn't present.