What a difficult time for your daughter, and for you as a mother. It is easy to understand why you would want to have a conversation with the other parent, who may not be aware of the effects her behavior is having on your daughter.
However, although it may feel as though confronting the other parent will help keep your daughter safe and healthy, the most effective way to help is to start with your daughter. Her comment about “doing something” could be her way of communicating that she is having thoughts of harming herself or someone else, or it could be a way of letting you know how upset she is. Either way, you cannot go wrong with verbalizing your love and support to your daughter and helping her understand that although the other parent may be struggling with acceptance, you are 100% on her side. If you are concerned that she may harm herself or someone else, reach out for help. This could be a call to her doctor or a therapist, or if you are unsure if you are able to keep her safe, calling 911 or taking her to an emergency room is a way to have her assessed immediately. Additionally, you will find a hotline and helpful information at https://suicidepreventionlifeline.org. The most important thing, again, is to communicate to your daughter that no matter what happens, you are there to listen, love, and support her.