Informal kinship care

MrsCactus9

I’m looking for some advice about informal kinship care. 

I’ll try to make this short.

My mum is 48 with a 3 year old son, she had him after her boyfriend (10 years younger than her) basically bullied her into having this child. She’s a functioning alcoholic and substance abuser (marijuana) and has borderline personality disorder. her relationship just broke down, originally dad wanted to take baby brother but has changed his mind since my mum didn’t fight (given she didn’t want this last kid) and she is now going to be a single parent at nearly 50. As I know, from experience, how much of a decent parent she isn’t. I was considering reaching out to offer her respite by looking after baby bro for a couple of weeks. But given how my mum would happily go to a child free life I can’t be too cautious. I’m 1 of 5 kids (including the newest addition) I’m the most obvious candidate being the only parent myself (to a 4 year old) out of all my siblings (they also agree baby bro would be better off with me) She doesn’t live in the same borough as me, so my main question is, being an informal kinship carer, I don’t get to make legal decisions for him. But she is unpredictable and I cannot guaranty she will come through. Me and my husband have a main income of UC as he works part time (but this isn’t a concern of money to provide, more a concern of court fees to get guardianship if it came to it) My mum would never let social services offer any help as to her they’re practically an enemy. Any help would be appreciated before I offer her the help, that way I can have my ducks in a row before anything happens. If you read all of this, thank you so much for holding on until the end.