No offense to you, my dude, but I don't buy the whole 'depression' thing the dev's trying so hard to sell us. Olivia's simply a spoiled, dumb, selfish bitch, the immature cunt who bluntly tells her mom, a caring, loving, supportive, attentive and dedicated single mother who'd jump in front of a damn bullet train or a tank and take a bullet for her kids, that she hates her just cuz her dear daddy, who never showed he gave a single flying fuck about her, was never around.
I know there's a general consensus among most men with a functional dick in their pants about single moms who used to be 'empowered' hoes in their youth and are crying their eyes out in the present that men don't want to deal with them and their bullshit after they clapped their cheeks, but in our case, the situation is drastically different. Lillian is a damn superheroine. This woman deserves a golden crown on her head, Superman's cape and a golden throne to sit on, cuz that's how awesome she was and still is as a mother. I'd argue that there's more to the story she told the MC about his stupid, abusive dad doing a complete 180 like that, she's only human, we all make mistakes, BUT Olivia's at least 18 yo in the story and knows or should know perfectly well what a great woman and mother Lillian is and should've thought at least twice about the words that came out of her dumb mouth instead of falling into a supposed "depression" after the MC called her out for what she did, a pretty convenient excuse for an immature, dumb brat who can't take responsibility for her own actions.
A lot of ppl do and say stupid things when being angry they later come to regret, but you don't talk to your parents as disrespectfully as you'd talk to one of your friends or a random person on the street, especially not to a mom like Lillian, who always had both her and her brother's best interests in mind and worked her ass off all her life for their well-being and future. The fact that she refuses to apologize to her under the excuse that she's too 'depressed' and can't face her mom makes it worse, cuz Lillian's time is limited, she dies in the 2nd Ch released prior to the Reworked Ch1, IIRC, and I don't think she'd mind her daughter talking things out with her, apologizing for the harsh words she told her and spending as much mother-daughter quality time together as they can.