Becca made the logical decision to reach out to Ben’s mother. I would have made the same decision that Becca made. Becca was desperate for help and was hoping to have some support from Evie’s grandmother. Of course, Mildred was ultimately a dreadful and controlling woman, but there was no way that Becca could have known that since Ben never really talked about his mother.
Such a tough decision! Under the circumstances and due to the time period I would say yes to seeking help from Mildred. However, Ben’s behavior towards Mildred would certainly give me a reason to ponder over it until absolutely necessary.