Not really sure what my question is here, but I found myself in a situation I’m not really sure how to navigate.
My 17 yr old DS is in a relationship with a really lovely girl who, as is becoming increasingly apparent, has a chaotic and I suspect traumatic family situation - police and SS have been involved And she no longer lives with her mum 
My first priority is obviously to my son and I’m concerned that he is hearing some difficult detail and often having to give comfort and advice that I feel is probably beyond his maturity. I have tried to speak to him about it, but he doesn’t want to break her confidence and says it’s nothing he can’t handle which I get but he is besotted and knows no better.
I’m also wanting to extend kindness to her, make a feel welcome & I suppose also model good parenting but I’m worried she will become too dependent and invested in our lives. I also feel I should say something to her to acknowledge that I know her home life isn’t always easy but that she always welcome at our house or can talk to me, but again, don’t want to overstep and this feels a bit much as she’s only really started feeling comfortable eating a meal with us as before she didn’t want to be a burden, was worried about leaving food and there’s clearly lots going on there that we don’t know about 
has anyone been in the situation and can advise where my boundaries should lay both with her and in terms of my son’s relationship with her. I have had a very open and robust conversations about Contraception with him and also kindness, consent, healthy relationships etc. I am so proud of how kind and considerate he is showing himself to be but this is his first love, he’s only 17 & I don’t want him to feel like he needs to save her or that she can’t cope without him as we all know very few first loves are destined to last.
She is also 17 and they’ve now been together 5 months.
Any advice?