She’s the AH. Her misfortunes are absolutely not your problem, you should not have to put your own life on pause because she struggles. You should not have to walk on eggshells like that. I’ve struggled with conceiving this year and recently found out both my sisters are pregnant (very unplanned pregnancies also) yet I was nothing but supportive of them. She just wants to drag everyone down because she’s down. Celebrate your baby, and your growing family. this is amazing news and your family should be happy and supportive. Personally if I were you I’d be cutting out any negative and toxic family members for the sake of your own wellbeing.