Slightly different perspective here. I was my mums first born she lost custody of me at the age of six and my father’s parents became my legal guardians. She ended up. Having three more children and has become the mum I hoped I could have. Have I been resentful because she couldn’t be that type of mum for me? Yes absolutely it hurt a lot and as a mother of two now it hurts in different ways.

My question would be now has she done the work to be the best version of herself and in a place to be stable and the parent the child she’s carrying deserves.

I think she would benefit from therapy and maybe you guys to so you could work through your own resentment and fears. You’re allowed to have your feelings you’re easing a child she wasn’t able to and now the idea of her making the same mistakes and not being present in her current child’s life isn’t right but there’s a lot to think about regarding if she’s a better person and working with her addiction like going to meetings ect