BPD and mental health challenges for son and girlfriend with new baby

hi @Sasha5 sounds like your son and his partner are going through a lot right, especially with a baby in their care, it must be really tough. it's understandable that you'd be concerned for them, and i'm sorry to hear how heavy it's been to carry this around.

you mentioned that they 'both want us to rescue them', what does the 'rescuing' imply? is the financial support?

i'm also curious to know, is there a reason why your son and his partner aren't willing to call for support? i know it's incredibly tough when they're not willing to call, the best we can do is gently continue to encourage them. the safety of the child is super important, do you feel the child is at risk? when fights occur, are you able to take the child to another environment (i.e. backyard, park, etc) to keep them safe? 

i'll like some financial supports below, in case you want to look into it:

• Ask Izzy
• Financial assistance | The Salvation Army Australia
• Financial support for families | NSW Government

your son's partner can also try the PANDA helpline (they have knowledge around perinatal support): New parents | PANDA

do you have supports for yourself? this is a lot to manage on your own, i do hope you have friends or professional supports you can lean on too. if not, feel free to check out Carer Gateway. you deserve to feel heard. we appreciate the incredible strength you shown in reaching out, and trying to help your family 💜

A someone with a BPD diagnosis, I have some insight into what might be going on inside your son's head.  I cannot give you a rosy picture - I wouldn't even wish BPD on the many perpetrators of acts that led to my mental health disorders.
Be there for them, even if you cannot be physically close to your son (for personal safety reasons).  Listen when they talk.  Demonstrate empathy and compassion.  The more you say, the greater the risk of bad thoughts entering your son's head.
Dialectical Behaviour Therapy is reported to be the best option for people with BPD.  I've started it three times - never made it past the first module.  However, urging your son to try DBT is probably the best option.
Finally, never dismiss your fears about things your son might say or do.  The only positive story that I have in relation to 000 responses for mental health is that I'm still breathing.  I hate the people who made such calls for a long time, but I eventually appreciate what they did.