Hello,
The pronoun issue can be a complicated one. My partner and I frankly don't care what people say, and don't expect people to use the "correct" prounoun. Think about it in other situations: would you be mad that someone didn't call you the correct racial label? Wouldn't it be better to just have no label at all? We also don't think it's realistic to expect family to change. If they have known a person since childhood as one sex, it can be hard to make that change. If they can do it easily, great, if they struggle, don't hassle them about it. They're (probably) not doing it to hurt anyone.
One major difference to add: this is not like racial slurs, because the person is (again, probably) not saying it to hurt anyone. If they are, the fact that they used the wrong pronoun is a lot less troubling than their motivation.
Alternatively, you can always recommend non-gendered pronouns such as "Hu" as an alternatively. Overall, being upset about what pronouns people use or don't use to describe you or your partner just gives an awful lot of power to other people that they don't deserve or need. Maybe this is an unpopular opinion, but it's easier to pick your battles, and if we had to choose between him using Men's restroom and being called an occasional "ma'am," we'd take the restroom any day.
Joe