AITA for telling my sister that her "boundaries" are just an excuse to not show up for people?

So some context: our mom had a minor stroke last month. She's okay, recovering well, but it was scary and we needed people around. I (32F) live 45 minutes away, my brother (28M) drove in from out of state, and my sister "Cara" (35F) lives literally 12 minutes from the hospital.

Cara showed up once. For about an hour. Then said she was "overwhelmed" and needed to "protect her peace."

I didn't say anything at the time because I was exhausted and didn't want to fight. But two weeks later at a family dinner, she starts talking about how she's been "doing the emotional labor of processing mom's health scare" and how hard it's been on her.

I just… snapped. I said something like, "You processed it from home while the rest of us sat in a hospital waiting room for four days. Your boundaries are real when it's something you don't want to do, and suddenly invisible when you want support yourself."

She started crying, left early, and now has me and my mom blocked (my mom!! who just had a stroke!!) and has been texting my brother saying I "verbally attacked" her.

My husband says I was too harsh and should apologize to keep the peace. My brother privately agrees with me but won't say it out loud because he doesn't want to get involved.

I don't think I was wrong but I'm starting to second-guess myself.