Looking for some advice.
DS and her female friend have both been (repeatedly) sexually assaulted by their mutual (male) friend (coercing them into sexual acts, physical touching without consent). I am quite close with the female friend and she has been honest with me about that has happened and I am offering her support. We know my DS has also been sexually assaulted because when she told my DS about her experiences DS said that he had done the same to her. DS has however downplayed the severity of these acts, I think partly as a way of protecting herself emotionally and partly because she is being manipulated by him. Since this conversation DS and their abuser have become increasingly close, from an outside perspective I think they are in (an abusive) relationship. The female friend has now, understandably, cut all ties with my DS - DS began to gaslight her and insist that neither one of them have been abused.
It is the female friend who has told me about all of this, DS isn't aware that I know, DS maintains to me that her and the abuser are just friends and nothing more. DS has told me that her and the female friend are no longer speaking, she's said it's because the friend is delusional and lies all the time. I'm very reluctant to let my DS know what I know because, if I do, I fear I too will be demonised and pushed away. I want her to be able to tell me in her own time when she's ready.
He was also extremely emotionally abusive to the female friend, calling her names, shouting at her in front of people, saying he wished she were dead etc. Additionally he has been diagnosed with depression earlier in the year and before female friend cut contact with DS, DS (in response to his outbursts) would often mention he 'isn't in a good place' and that she needs to support him. I suspect he has been threatening suicide as part of his emotional abuse.
I have expressed concern to her, but framed it in the way that I know he has mental health problems and I'm worried that she's giving him a lot of support and she needs to prioritise her own wellbeing. I've also pointed out that she has a pattern of romantic partners with deep issues who she tries to 'save' and that although it is admirable that she is a caring person who wants to help people, this has ended badly for her in the past and she deserves better.
Basically I wondered if anyone has any advice about how best to support my DS. On one hand I feel I need to remain a person she can trust and talk to when she's ready and I want to let her come to me in her own time. On the other hand I'm scared that each day they are together he is gaining more control over her.
I love her so much and want to protect her and I don't know how best to do that. From reading posts I'm aware that sadly there are a lot of women on here who have been in abusive relationships and I wondered whether there was anything friends or relatives did that significantly helped, especially prior to your realisation that the relationship was abusive. Right now I think he has successfully convinced her that he isn't abusive and that it wasn't sexual assault.
I realise this is very long so thank you for reading.