Yes, I totally get that! The concern for them, possibly mixed up with lots other emotions? Maybe anger at him for doing this again, frustration at the new woman for thinking she can change him when you couldn’t?
If she’s never been in an abusive relationship before, she’ll fall into all the same traps that we did – not understanding red flags, thinking he will change with her calming and steady influence, hoping for a happy future.
The impotence of knowing that there is nothing you can do to help her or his Mum must be like watching a car crash that you can’t stop.
But there really is nothing you can do to help them.
Perhaps have a chat with whoever told you this and ask them not to tell you any more about him. I know that is hard, for all sorts of reasons. The emotions it stirs up are only reopening old wounds and you really don’t need that.