I definitely get the impression that Ruby's had a big hand in bleeping up that family and her parents have screwed both their kids up by mollycoddling Ruby and spoiling her rotten all of her life.And the whole family seemed to be doing better too. They threw parties, they had a houseful of guests, normal stuff. Now it just seems so bleak. I wonder what it's really like in that family. Is Ruby's unwellness casting a pall on the family or has a dysfunctional family contributed to Ruby's poor mental health?
She spent all her teen years and university life throwing tantrums if her parents didn't show her attention. She made her parents drive across the country and back every weekend to collect her from uni and drop her off again and bitched and moaned if they were a minute late (even if she wasn't ready herself). She was sending mummy endless letters and making her send her pointless care packages to enable Ruby's childish boarding school fantasies. She had her parents taking all their holidays in Devon so they were near her while she was at uni (and naturally made them come pick her up to join them so they never had time alone).
All the while Mummy Bones has been writing bad poetry about marital rifts. Ruby's mentioned her dad sleeping on a pull-out cot outside in the summer. Martha's mentioned that she's often excluded from/forgotten about when family events/holidays are arranged and Ruby sneakily tried to exclude Martha from attending her graduation. Martha usually does thoughtful things for birthdays/Christmas and in return Ruby gives her thoughtless, low-effort crap. Martha also chose to move to Brighton rather than be anywhere near her family, which doesn't seem like a coincidence.
Maybe that is all a coincidence and maybe their family would be just as much of a mess if Ruby weren't there, but I feel like never being able to spend a second alone with your spouse because of the spoilt, attention-seeking overgrown baby sucking all the life out of the house and treating you like an on-call chauffeur/camera operator isn't going to help a marriage. And always treating a child like an afterthought and neglecting them in favour of a self-absorbed, tantrum-throwing older sibling isn't exactly a recipe for a tight-knit family relationship, either.