the 'You could clean up your paintbrush at least' comment from her mom is sending meeeeee...... But also it makes me wonder - what can her parents actually do?
Ruby and her behavior actually remind me a lot of a girl I know. She's gonna be 29 this year, she's still a student - IMHO more because she doesn't know what to do after finishing uni than out of the wish to gain more knowledge - lives in a shared apartment with other students (who are all around 20), and has a part-time job in a supermarket. I love her dearly, but she is so obviously - like Ruby - stuck in the stage of thinking of herself as a teenager (or a child, in Ruby's case). This girl I know already has one master's degree, but she went on to study for another bachelor's degree, stayed living in the same room that she got when she moved to the town to pursue her studies and has been doing the same part-time job for ages. I think it kind of made her stuck in one place mentally - e. g. all of her original roommates (with whom she moved into the shared apartment) have finished their studies and moved out, got jobs, moved in with their partners, and new "generation" moved into the rooms, so while she is gonna be 29, the people that now surround her are almost all like nineteen, twenty (undergraduate students). And I honestly believe it gives her the feeling that she is also only twenty. She even sometimes says things like "once I'm older" - as if she wasn't old enough to make her own decisions.
I see a lot of this in Ruby, in the same sense that she does pretty much the same things she used to do when doing her A-levels. She still has the day structured in the same way, she's still staying in the same room, she still "obeys" the rules of the house (in the sense that it's her mom and dad, and she's the child who doesn't (have to be) responsible for themselves; she doesn't exist separately from them). When I was at home during the lockdown, one of the first things I did was that I rearranged and cleaned up my childhood bedroom - I was also a uni student, like Ruby, at the time and I was spending most of my time away from my parents home, but when I was stuck back at it, it made me feel like I was 12 again, and I didn't like it. So I put away my toys and old pictures and stuff like that, to make myself feel more like an adult. It was really weird for me to be back there all the time, since I went to uni and had a part-time job and had friends that my parents never met etc. but suddenly I was back in the same spot as when I was a child.
The problem with Ruby is, she never "reinvented" herself as an adult. She never spend a long time alone (in the sense of not being with relatives), and even her uni experience seems to have been a bit in vain (she came to a place where she wasn't the most special girl, and it seems like she didn't enjoy it a lot/didn't profit from the opportunities?), she didn't get a job/internship where she would be surrounded by others her age (but not from her family circle) to kinda see where they are at in life...
But idk what can her parents do. I think she has a very good relationship with her mum, so I don't think her mum would want to "throw her out" of the house - also, remember that it was her mum who recommended her to go to a therapy. I honestly don't think her mum is indifferent/careless (and from what Ruby says, if we can believe it, I feel like Marfa is also close with their mother - Ruby claimed they do spa days and movie watching together when they're at home; I feel like it's just that Marfa likes to pose as this "black sheep of the family", too extravagant and different to fit in - like some teenagers sometimes do, to feel like they have something to rebel against, although they migth have a great family background and relationships). So yeah, her mum won't send her packing, but at the same time, I can totally see her losing patience with Ruby just sitting at home doing barely anything (and apparently leaving dirty brushes all around, lmao). after all, Ruby is an adult, supposedly responsible for own health and happiness, and even if her mother recommends/suggests something, there is no way Ruby is obliged to listen to her - and I just don't think her mother would have the guts to e. g. start demanding rent from Ruby, or demand her to do important tasks/chores (since Ruby can't even drive so it's not like she can go shopping for the family or run errands etc.).