I wasn't sure where to post this, so apologies if it's in the wrong place.
I'm looking for advice for my sister, she doesn't have Mumsnet, Netmums or the like and I'm always banging on to her how great they are 
Anyway, looooong story short, she is 35 - 3 years ago, her 2 children were taken away by their father as she was an Alcoholic, fast forward 3 years, she has worked very hard and now has the kids overnight with her weekends, as she doesn't drink anymore and has quite impressed her Social Worker etc. last year, she had another baby with her current partner and although SS had to make sure she was ok this time (as she'd had bad PND with the others), were happy with everything but advised that if her and her partner ever split, they'd need to know as her partner is looked at as being the protective element in the relationship.
Anyway, major rows later and things pretty much going wrong with the relationship, she found messages on his FB to his brother, telling him he's going to contact SS and take away baby and leave her 
What rights would he have? Would SS intervene? Would her baby now be taken, even though she is doing nothing wrong now but they see her partner as being her reason for keeping on the straight and narrow?
Any advice appreciated x