Would you address this issue with your partner's family?

I haven’t posted anything related to my relationship in a long time so I was just wanting some insight, lol.

Every time my boyfriend’s sister goes out with her coworkers she always ends up drunk and needing a ride home. They get together once a year and the past 3 times she always ended up calling her brother (my boyfriend) and I to pick her up. So we just drop what we’re doing and pick her up…

It happened again on Saturday. I was super annoyed and I mentioned to my boyfriend I don’t mind us picking her up if she had asked beforehand and gave us a heads up but for us to drop what we’re doing and pick her up every time she’s out with them isn’t cool. LUCKILY we happened to be going home at the time she called us this time…Plus she has her sister and her boyfriend if she needs to. My boyfriend got a little defensive and he said if we happened to be busy next time, someone else can do it.

I highly doubt that because we’ve been the ones picking her up. I think it’s pretty sad if she can’t call her bf to pick her up. He was even hanging out with us at the time! She just asked us to avoid an argument.

I thought it was dumb my bf got defensive because this really isn’t acceptable if she expects us to drop what we’re doing. Next day she said “I feel bad that I ruined your night” and I’m thinking “Why do you do this then?”