R.K.'s manga / #Modern k(1)

Ch. 63 -ch 60-62ish: Grayson suddenly misses his birth mom and completely rejects Kaitlyn after he originally started calling her mom? Idk, with Cole being all upset over Grayson wanting birth mom who abandoned him, I thought he would still like Kaitlyn since she's the one still being sweet and not yelling... How long has it been since birth mom left again?