Because if you remember the chapter Sohoo visited the mom, she told him not to let Merry go to the funeral.
Why tho? I mean, that makes no sense, he's going to find out sooner or later, why can't he attend his own mother's funeral? That's just sad.
Because she didn’t even tell him she had cancer, in her own way she thought him being clueless to her death would ease the grieving.
But the mom told him not to say anything so he respected her wishes.
Why didn't he just tell him his mother died wtf if I was Merry and my lover had not told me that an important person in my life had died, I'd be so mad and more grateful towards the mother for showing me what had happened.