DH's younger brother and his sister in law were always in YH's corner. DH's older brother was in her corner even…
One thing that the show demonstrates very clearly is how welcoming the neighbourhood and DH's friends and family were to people that genuinely wanted to be a part of them, like JA and DH's brother's girlfriend... and also to YH, frankly, if you consider DH's younger brother, the sister in law, the welcoming the friends gave her at DH's party, DH's mother attitude at the party, and generally the tsundere but still concerned for her attitude she took (old fashioned, but fundamentally feeling sorry she "had to work"... it's not as if YH was thinking about leaving work once he got a promotion, and she apparently had enough money to pay JA and let her live on the run, while DH had a very poor bank account and yet still got money from it to give his brothers, telling them it was from YH... and let's be clear, it's not as if you can substitute care for money,, in that respect DH's mom taking care of YH's child while she pursued her career, or DH's brothers and sister in law treating the kid as family, count a billion times more than a transactional favor done in order to get into DH's good graces and be able to manipulate him into giving up his relationships with his friends and family, for the sake of her petty jealousy.... YH quite simply never cared about DH's family and friends, indeed claims DH shouldn't consider the former family, and that she hates the latter, whether true or not... and, again, it's not as if, imho, she even needed to care about them, but she certainly needed to accept that DH cared about them... instead, she hated iron for not being steel, she bought a motorcycle and was angry that it didn't have four wheels-.