Kids' mom often posts pictures of herself and the oldest as her main pictures on social media. Whenever there is a picture of the younger (scapegoat) child it's almost as an afterthought and you can usually hardly see his face because he's at some angle.
I've seen that too. uBPDbm always looks so rigid and uncomfortable with her arm around SD10. It looks forced. Or it's "Hey, look at me, I'm being a mom!".
If uBPDbm posts a picture of herself with SD10, SD10 won't be wearing her glasses. Does her mom make her take them off to appear more attractive?
All of uBPDbm's facebook profile pictures are of only herself, usually not wearing much clothing, and they're almost all selfies (control). I think she has a touch of narc/histrionic to go with the BPD.