@needtonamechange1000 This is bloody awful. Sadly however, not the first time I have heard shit like this. Stories of mothers BLATANTLY favouring the son(s) in the family. Particularly with (adult) children born pre-1980s.
Girls seem to be quite revered now and desired (especially by women,) but some 4+ decades ago, boys were hugely favoured and I knew (and still know) a whole host of women whose brothers were favoured. Treated like Royalty, could do no wrong, and always take take take, without ever giving back. Still, multiple sunbeams shone out of their arses........
I am not saying boys are NOT wanted or loved these days, but many people want a daughter. At least one daughter anyway. And neither one is favoured these days (not as much as a few years back anyway.)
I have lost count of the amount of women (45+) who I know, whose brothers are favoured. No matter what they do, the mother favours their brother(s) and they can do no wrong. I know a few women whose brothers only visit their mother 3-4 times a YEAR (for a few hours,) and they are still worshipped. Yet the daughter(s) are there 3-4 times a week, and are treated like shit. Go 2 days without contact, and you get 'I thought you were dead/in a coma/had gone abroad!' 
I would literally ghost her OP. I'm not kidding. She has been an utter fucking bitch to you. I am sorry to say that, but what she has done is nothing short of utterly disgusting. She does not deserve you. Let her get her precious fucking SON to be her handmaid, along with his missus.
ARGH! I am fuming on your behalf, seriously! 