She just can't help herself!!!

A couple of months ago I posted about my husbands brothers girlfriend drinking throughout her pregnancy. She just had a baby last November and all through her pregnancy she drank wine. Her and her partner thought it was normal. Anyways me and my husband conceived a baby in January and unfortunately suffered a misscarriage it was so sad as we both wanted it so bad. After agreeing to wait for a few months to "heal" and months of sadness and depression in the middle of it all we found out his brothers girlfriend was pregnant again and to make things even worse she's due the same time as we were meant to be due. This caused my depression to be worse. As time went on we have been ttc again and iv been perfectly normal however tonight I was scrolling through his brothers girlfriends page and they had pictures of them out and she was drinking!!!!!! I can't help but stress for the health and wellbeing of their unborn baby and I find it so selfish!!! They know about our mc which is what is making me even more angry I feel like they are rubbing it in our faces!! Like I said in my previous post from months ago they have a very toxic relationship they both cheat on each other, are both riddled in Stds and there relationship is violent. My brother in law (who I don't like much) hits her and throws her about the house (infront of their baby) and they both drink around the baby. I can't help but feel so angry towards this problem. It's hurting me so much i feel like messaging her and saying something but don't know how to word it. I have deleted all contact from them and even told my husband I want nothing to do with that side of his family. My husband doesn't even seem bothered about it but he is so calm I don't even know how! He says he is angry and it is bang out of order but he won't say anything to his brother about how this is affecting my mental health. I know he wants to keep the peace in his family which I respect but I can't help the way i am feeling. People like them are given gifts of children and treat it like an advantage. If we conceived our baby any time soon it would be a blessing for us. I'm so heartbroken angry and hurt. What can I do :(