Hi @B33
Welcome to the Forums and thanks for sharing a bit of your story.
It sounds like a really concerning situation with your brother. It’s so hard when you are also concerned about a child in his care.
It’s good to hear that he is seeing a counsellor. Although a diagnosis can be helpful in knowing which treatment path to take, if he has a good therapeutic relationship with his counsellor, that can be a huge help with or without a diagnosis.
A diagnosis can be provided by a clinical psychologist or psychiatrist. The best starting point is for your brother to visit his GP. They can give a basic mental health assessment and can refer him onwards as appropriate.
If you’re ever concerned about your brother’s immediate safety, it’s important to call 000 to have a welfare check from police.
Encouraging him to reach out without making him feel bombarded can be tricky. It can help to keep letting him know you care about him and are concerned. It’s also great to educate yourself about what options are available so that you can guide him when he is ready to take another step. You can also see if he is open to talking about his current counsellor and how that is going; and you can see if he is open to discussing how to keep safe when he’s thinking of suicide. I’ve linked a SANE fact sheet on this topic, as well as a safety planning app from Beyond Blue.
How to help when someone is suicidal
Beyond Now safety planning app
It is important to leave diagnosis to a clinician, but you have mentioned that you are seeing symptoms consistent with borderline personality disorder, so you might like to take a look at SANE’s information on the topic here:
Borderline personality disorder
There are a lot of members here on the forums that have supported loved ones with mental health challenges, so I’m sure you will find plenty of guidance and support here. Please keep posting 🙂