When social media tells you more than the actual person

[MonteStory]

My SIL is a tricky person to have a relationship with. She has a personality disorder and generally behaves like an unruly teenager (she’s 28).

In the last year or so I have found out some fairly important life events through Facebook rather than through her. I’m often not sure whether her own parents (who see her a lot) know this information and it’s obviously not my place to share it.
Eg:
She has a new job
She has a new partner that she’s living with
She had her bag stolen
She went to court over something

Each time I see big news like this I think ‘gosh I wonder what’s happened, I’m sure PIL will tell us about it when we see them’ and it is never mentioned. I only usually see her with the PIL so I feel awkward bringing it up in case it was something she didn’t want them to know. I’m also fairly certain half of it is lies and I’m not comfortable publicly embarrassing her, no matter how much it annoys me.

At the moment I’m feeling particularly awkward as if her fb is to be believed then she is actively lying rather than just omitting details. She hasn’t been able to come over sometimes when we’ve visited because she’s been working but her fb makes it clear she has been out drinking. Her mother tells me funny stories from the house share that she lives in but her fb (photos, references to ‘our house’) makes it clear she lives with her partner.

She knows I am an fb friend of hers so the impulse to comment on her ‘omg guess what’s happened!’ statuses is becoming very strong!

I know some will say the obvious answer is don’t follow her but at the moment she seems to be in self destruct mode and I genuinely feel I need to keep tabs on what she’s up to.

Do I comment? Do I leave well alone? Do I call her out face to face?

My sil is like this. I don't know what she gets out of it. I must say though I do love the ones where she just tells a complete porkie like last year when they went on holiday, she posted "house immaculate, done from top to bottom..." the thing is they live with my dad and I went up to help him put his blind back up that their dogs pulled down and it was like the place had been burgled! I mean why?? Like you said, actively lying rather than omitting details or just not posting inane random shite! Just to add my dad practically lives in his bedroom when he's not at work and they've taken over the house so he's more like their lodger so he refuses to tidy their shite up.

As much as it's tempting to comment or pull her up on her lies it might be made out that you're the bad guy for embarrassing her.

This is why I won’t be friends with MIL on social media. She’s toxic and I don’t want to get sucked in.

Some of the online stuff is lies I think (she said the person who stole her bag had a knife for example but her Dad, who was with her, said it was knicked from under their table and the person didn’t even speak to them let alone threaten them).

But the more key stuff, like where she’s living, I think is true so yes it’s the face yo face stuff that is lies. I think that’s why it annoys me. She’s happy to share these important things with her online ‘friends’ but not us, in full view of me and lots of other close family friends who know their parents.

is she a vulnerable adult?

if not, I'd just unfollow and ignore.

She has a personality disorder which causes the emotional maturity of a teenager.

sorry OP, I don't know enough about that to know if it means she is classified as vulnerable.