Katniss's mom is more of an absence than a presence in Mockingjay. Although Katniss gets to spend some time with her mom while they're both refugees in District 13, Katniss is busy training for her position as the Mockingjay and her mother seems every bit as busy working as a valued medic in the hospital.
After the tumultuous events of the war, Katniss and her mother are separated again. Katniss's mother is devastated by the loss of Prim, and we can't blame her. Finally, Katniss's mom goes off to help other people in other districts, because she can't bear to be in District 12, even if Katniss has to be. It seems like it's easier for her to help other people than it is for her to help her own daughter.