How should I treat my birth mother as a Muslim?

Salam everyone. I have a bit of a situation and I’m looking for Islamic advice. So, my birth mother left me soon after I was born. It wasn't simple-she was struggling with poverty, and after I spent two years in an orphanage, I was adopted, Alhamdulillah. When I turned 19, I managed to find her. She really wanted to rebuild our connection and was very loving. I forgave her, and now we have a lovely relationship. But some of my adoptive family, who don't even know her, are pushing me to cut ties. They say things like 'don’t trust her,' and that I shouldn’t worry if she gets sick or even feel sad when she passes away. They keep saying, 'You don’t need that in your life.' I’ve come across some fatwas that say we must still be dutiful to our parents, even if they abandoned us. My birth mother has repented and genuinely wants a relationship. I feel like Islam teaches us to maintain family ties, so I’m conflicted. What do you think, brothers and sisters?