AITAH for not believing my sister-in-law’s abuse claim against my brother?

I (F, early 20s) live in Pakistan in a joint family system. My older brother (Annus) and his wife (Rahma) have a 1-year-old daughter, Inaya. Ever since Inaya was born, my mother has been her primary caregiver — by choice, at first, because Rahma was struggling emotionally and we assumed it was postpartum depression. My mom stepped in and basically raised Inaya full-time. Inaya sleeps in her parents’ room from 3am to 11am, and is with my mom the rest of the day and night.

Rahma has a history of depression and anxiety, and uses an unprescribed cocktail of meds to manage it. She didn’t breastfeed Inaya, has referred to her as a burden multiple times, and has sometimes failed to give her medicine or report her symptoms accurately to doctors. She also hired a 15-year-old full-time nanny (who hasn’t been to school) to care for Inaya, which we found ethically concerning.

Things came to a head a few days ago. Rahma had the flu and spent the day resting and going to yoga while my nearly 60-year-old mom took care of Inaya. When my brother got home after a 10-hour workday and said he wanted to go to the gym to decompress, Rahma got furious and accused him of not caring for her. They got into a huge fight.

Then we (my mom and I) heard what sounded like a physical altercation. We rushed to their room. I didn’t see anyone hitting the other, but Rahma shouted that Annus was abusing her and told my mother she was “enabling abuse” and that “God will hold you accountable.”

I personally witnessed Rahma shove my brother to the ground during that fight. Later, she was standing in the living room yelling “Help me, he’ll kill me!” — even though my brother was in the bedroom and not physically near her. It felt performative and alarming.

The next day, she messaged me saying that Annus had “beaten her in front of my parents” — something I know didn’t happen (or at least, did not happen when we were there). She also said “next time he does this I’ll wrestle him to the ground.” That felt strange to me — in my experience, abuse victims usually talk about fear and escape, not about fighting back physically.

To complicate things further:

• My brother has a history of being abused as a child, and did harm someone in his teenage years. He’s confronted that, asked for forgiveness, gone to therapy, and has worked hard to change.
• Rahma comes from a neglectful home, and her sister suffers from extreme paranoia. I suspect some of that may be showing up in Rahma too.

I’ve always been an advocate for women and survivors. I’ve seen how often Pakistani men get away with mistreating women — and I don’t want to be part of that problem. But in this case, I find myself believing my brother’s version more than Rahma’s, and I feel horrible about that.

AITAH for doubting her?