I’m looking for some advice...

My sister in law has just walked out on my brother and my 18 month old nephew! My brother has epilepsy (mild) and minor mental health issues... they’re known to social services. He’s in an absolute state, I live an hour and a half away and I have a newborn and a husband who is vulnerable to covid. So I can’t go to him, luckily my mum is there. I can’t think of what I can do to help him, I’m so worried social services will take my nephew from him.

Has anyone been in a similar situation or has and advice on what I can do to help my brother, I feel so helpless.