Am I wrong in thinking that this is absurdity?

I hope this is the right place to ask. I have a stepdaughter, she is 9yo, today I was at Walmart and she was there with her mom and siblings, I was with my mother in law, they stopped to say hi and my mother in law asked her why she hasn’t called or texted her, she said that she had her phone granted for 2 months, when my mother in law asked why she said that was because she didn’t say hi to her mom’s boyfriend, to which her mom responded with “that is not fucking why your fucking liar, you had your phone taken because you’re a little moody bitch.” To which she laughed and I was kind taken aback and shocked, my mother in law said that she does it all the time and they’re used to it. I told my husband and he thought that it was absurdity that her mom talked to her like that. I don’t what I can do though, I know she isn’t my daughter but this isn’t the right way to threat or raise a child... my husband thinks we should try for her custody but we don’t have enough to prove she is better off with us. via /r/Parenting https://ift.tt/2OOsASx