Should I end the friendship...??

[shesaidhello1]

Yesterday 09:55 shesaidhello1

Hi all,
First post so please excuse any mistakes i make and apologies in advance for the long story!
Basically, I have been best friends with F for the last 10 years. As close as sisters, speaking and nearly seeing each other every single day, sharing everything with each other.
Both of us went through (a few) heartbreaking break ups in that time.
I then met someone and we were due to happily announce our engagement.
She had been messaging my first cousin IV who had a live in girlfriend at this point.
They both then asked my permission to start dating (even though IV still had this girlfriend!) I stated my fears, but what else could I do.
F & IV had a whirlwind romance and a month later also announced their engagement.
That's when things turned bad.
I never knew how controlling and horrible IV could be and is literally making F life hell. Mentally abusing her, controlling where she goes and when and who she can talk to etc.
F is just going along with it, refusing to come for girly meals out as we might go to places IV may not like. F has never told me the whole story about how bad it is but snippets when she's decided she can't cope anymore. F has asked how to break her engagement off but then the next day it's back to normal and they're all 'happy' again.
There was an incident involving a video at a friends wedding where IV shouted at F for talking to boys(!!!!!). IV basically said if I was such a good friend I would have stopped F from doing something IV does not like (wtf I know)
Since then F has stopped speaking to me. It's been 6 weeks now and I'm still so angry.
I've never neeeded to confront her about anything in the 12 years I've known her and I just don't know what to do and what to say.
I hate that F is marrying IV and just wish I could stop it and stop F ruining her life.

[TheLaundryLady]

It doesn't sound like she's in a place to listen right now
Abusers will always try and remove friends from the scene as it increases their power over the individual and isolate them.
I would message her saying that you will always be there for her anytime she needs you , there's not much more you can do