OP felt she was just looking out for her sister and snapped. She asked Reddit:
I grew up in a very abusive household. I graduated high school at 17yo so I could move out the day I grabbed my diploma. I couch surfed for a couple of months until I turned 18 and got my first apartament at 18yo with my boyfriend. We worked minimum wage jobs, working 60+ hours a week so my bf and I could afford rent.
When we moved in, we only had a bed, a small 30 in TV, my bfs xbox, and toiletries. Nothing else. Over the next two years, we began saving up money to get our first car. After getting a car we applied to a job that paid more for fewer hours. We get raises every few months and profit sharing every quarter.
We slowly began to update our apartment. Now, the only thing we were missing was a couch. The couch was donated to us by our apartment. Someone got evicted from their unit and left everything in there. The office, knowing we don't have a couch yet, gave us the couch.
After all of the upgrades we decided to start hosting D&D at our house, just me, my bf (the DM), my BIL, and my sister who weighs a whopping 375 lbs.
My sister couldn't fit into any of our chairs, so she sat on our couch. We originally didn't have a problem with this until we noticed our couch began to divet in the middle, and the bar that held the futon together underneath started to bend.
My bf and I agreed we'd buy her a chair that's built for her weight. The chair just came in, and we had D&D on Friday. We showed the chair to my sister, hoping she would be grateful, we paid over $100 for this. We're not rich, so we had to dip into our savings to pay for this.
My sister got mad at us, accusing us of calling her fat.
We tried to calm her down, but trying to calm her down just made her scream more. My BIL was telling us to look at what we started, I have to go home to this. You got this couch for free, just buy another one, etc.
With my sister screaming in one ear and my BIL talking in the other, I lost it.
I said (summarizing): 'Everyone, shut the f**k up! You are completely right! Your fat a*s is breaking our couch.'
'You can lose weight easily but choose to stay a fat, slob. This is a problem you can literally run from, but you chose to be fat and collect taxpayers' money to stay home and eat more and gain more weight. Until you lose weight under 250 lbs. you're not allowed on our couch again.'
I admit it was a bit much, and I should have a better control on my feelings. I feel bad for saying what I said on Friday, but it felt good to finally say it.
Last night, my BIL was texting me, saying my 'bullying' caused her to have a mental breakdown, and I should apologize. I told him I'd apologize when she apologizes for bending our couch. AITA (Am I the A-hole) for calling my sister fat by buying her a chair that supports her weight?
Reddit users were not on OP's side but OP always had something to say back:
YTA (You're the a-hole). She's mentally unwell. It would be akin to calling someone with schizophrenia a 'f**king lunatic'. You think that's going to help that person? It just makes you feel good. She's sick. All fat people are sick.
I've dealt with weight issues my entire life because of our mom. I got therapy and got the help I needed. I lost, gained, and lost again. I've kept this one off for a while. I offered my sister the same help but she refuses every time. My family staged an intervention but it's useless.
She stopped going to the doctor because they tell her she won't see 35 if this keeps going. I've been that size, I've lost the weight with the therapy, yes I gained back, but that's because I quit therapy and went back. I was sick, still sick, and I've tried to help her and her husband just enables her, too.
YTA. Not for wanting your Sis to sit in a chair made for her, but for the fatshaming bullsh*t you said to her.
She can sit in the chair we bought her just not our couch. We spent over $100 dollars for this chair the we even said she can keep.
You're not listening. You are NTA (not the a-hole) for the chair. YTA (you're the a-hole) for the fatshaming bullsh*t about 'choosing to be fat', 'can lose weight easily' and not to forget the being lazy accusation.
YTA. I love that you complained about growing up in an abusive environment and then detailed all the emotionally abusive things you said. Just love that for you.
I feel bad for what I said. If I could take it all back, I would. I've struggled with my weight my entire life. I went to therapy to cope with trauma. My therapist gave me a weight loss plan. I lost, gained, lost, gained, and lost again. I'm hoping to keep this one off.
I've offered the same therapist to my sister hoping she can take her health into consideration. I understand my actions were horrible and ludicrous, I'd take them back if I could. The last thing I'd want is to wake from a call saying my sister died before 30.