DD14 is year 10. She has had a large friendship group since year 7 with one girl closer than the rest (A). A has experienced ACE (adverse childhood experiences) with an alcoholic father who was moved into a shelter facility last year. Over the summer I became aware of an intense level of non stop contact from A demanding rapid responses. The messages are a mix of 'we belong together' 'only we understand each other' type message and a lot of derogatory comments about others. DD has notably not joined in the unkindness. I have been called a 'hairy lesbian' DH a 'useless faggot' and other nastiness when DD hasn't been able to respond immediately. Other friends have been pushed aside and critised and a brief flirtation of DDs with a (lovely) boy was ridiculed with him being called a 'pussy' and a 'faggot' and A telling DD he had told everyone she was 'frigid' (which I doubt and DD questioned). 4 weeks ago A took an overdose of prescription medication she had stolen from her father. This was in response to DD not replying to messages (DD was playing outside and didn't have her phone). Now she constantly tells DD she is alone and thinking of harming herself.
The messages are constant. 16 received last night between 1am and 5am (DDs phone is downstairs). They are all:
I love you, you are my life I need you
You are so beautiful
No one understands you like I do, we should always be together
You don't care about me, you don't reply, I feel so low
Your mum is disgusting not letting you have your phone, it's your right, she is such a smelly bitch, she should fuck off
I feel like I it's going to happen again
I need you, no one else understands
etc etc
etc etc. I am struggling to know how to handle it. DD is clearly upset and struggling. I want to support A but cannot allow DD to be manipulated. It's all such a mess. Advice recommended please, I am very concerned.