Hm I don't think her brother had poisoned her, I mean he seems to deeply care about Ercella. Same for her husband, from what we saw in the flashbacks 🤔
I succeed to read the sensored parts, it's almost accurate :
I had an older brother. My older brother was very good-looking and always excelled in his studies. He was the best in everything he did.
Everyone loved my older brother. He was always the center of attention.
That older brother, was my...