Lealdade familiar ou proteção ao sobrinho?

I 25F have an older brother 28M. Growing up my mom spoiled him a lot and still has a

habit of excusing his behavior because that's her son. This situation has completely fractured

my family, and now I'm being told I'm a terrible sister. My brother was in

a long-term relationship with his ex-girlfriend Lena 27F. They have a son together who is

now 5. Lena and I became very close during their relationship, and even after they

broke up, I stayed involved in my nephew's life. I babysit, help with school

stuff, and I'm basically one of his safe adults. When my nephew was

around 2, my brother left. Not just emotionally he abandoned them. He moved out,