Yeah, you need to make more Progress with Meredith. The attic stuff is "extra." You need to go through a few things that will make MC more "enthusiastic" about spending time with Mom.
I looked at the code and the "Boys Will Be Boys" perk is required. You get that after the second Kissing scene. Use MC's bed (to lie down) and select "Jerk Off" and select "Meredith"
