This is not about me. It's about my SIL.

I gave birth in March and she gave birth in May.

Her and I really got close through our pregnancies because we had a lot to relate on and talk about when it came to being pregnant. She seemed so over the moon and excited due to my brother and her struggle with infertility issues and they have one child they had 6 years ago and really struggled to conceive both.

When she gave birth she was a very protective mother to her newborn and everything seemed to come natural, she was very dead set on breastfeeding due to things not working out when she had my older niece.

So when she was 2 weeks postpartum she was worried she had pp depression. I told her it's a good chance it still could be baby blues and to talk to her doctor. She followed up with her doctor and I never heard much after that. (Not my business so I didn't ask too many questions )

She had a nice amount of maternity leave and was at home with the girls for a period of time and went back to work middle of August. A family member watches the kids during the day while she works from home. And my brother works full time also.

I went to see them this last weekend and she was not home because she was out drinking and having fun with her family and my brother was at home with the girls. My brother opened up how hes had the girls the last 4 weekends in a roll and she has hardly spent any time with them. He said everything else is a priority other than being with the girls. She got home at 6 pm and she was a bit intoxicated and the first thing she did when she got home was started drinking more, she didn't interact with her 4 month old all night (my brother was taking care of her) almost until 11 pm when we decided to head home. And even then she was too drunk to interact with the baby anyways

My brother told me that there marriage has been struggling and when they fight she likes to threaten divorce, and she is very detached from their 6 year old and 4 month old. He noticed a bit change when she decided to quit breastfeeding because she wasnt to be able to drink without worrying about the stress of making sure she had pumped milk, etc.

I am worried it sounds like maybe she postpartum depression may have not been fully addressed and I want to talk to her but I am scared of offending her or something. Her and I were very close while pregnant but now I never really hear from her.

She told me she wanted to spend a lot of quality time with their 4 month old because it's there last child

How would you handle this?

I want to help her but I am not sure how to reach out ...

Any advice.