Mil crossed a boundary

For the sake of wanting to stay anon, I will change out names. My oldest SIL “Melissa” is 25, my other SIL “Veronica” is 23. Then there’s my mil and fil. So my fil was never really in my husband’s and his siblings’ life for a while after him and my mil split. At one point my mil took my husband and Veronica and moved out of state and left Melissa and their oldest brother with my fil. Melissa then joined them here in California and soon after my fil came but got an apartment for himself. Since then, Melissa went no contact with him. No one knows the reason why as she’s never told anyone about it. Her siblings have always given her shit about it but she stood her ground and as she should!! She made it clear she didn’t want him meeting her kids. She has her kids every other week and on her Friday’s, my mil watches them while she’s at work. Well I guess my mil told Veronica that she sneaks my fil into their apartment to meet the kids when she’s at work 🤦🏻‍♀️ I feel like that’s extremely disrespectful to her daughter. Veronica told us last night as we had all gone out to eat. Melissa wasn’t there because she went no contact with Veronica as well. Veronica laughed about. My husband and I were in disbelief and told her that wasn’t funny. She responded with “fuck that bitch” and continued to laugh. My husband told my mil, who was sitting next to me, that she’s crossing a line doing that. I really want to tell Melissa but my husband told me to stay out of it, that it’s not my business. But how is that fair? Her kids are 3 & 4. Soon they’ll be able to understand and end up telling Melissa that their grandpa visits them when she’s not home. This honestly made me lose a bit of trust in my mil as well.

I also think my husband doesn’t want me to say anything because Melissa and my mil live together and Melissa would most likely kick her out and she wouldn’t have anywhere to go since I don’t think she’d be able to afford a place by herself. I’m honestly hurt for my SIL. Her entire family has always been against her. And I know she has her own problems but after a lifetime of traumatic events, I understand her. I don’t know what to do because I know I should tell her but I know my husband wouldn’t trust me after.