Keep going......I have seen mothers who have been very sick with complications take a REALLY LONG TIME to get a full supply.  If she lost a fair amount of blood at delivery and now has a wound infection, she qualifies!!  If she is exhausted, I'd let her go once at night four hours to get some more rest--she does need to heal--and make up the pumping during the day.  I believe someone (?Winnie) discussed pressure points in the back for increasing supply/let down.  I tell dads to massage their wives' backs.  Relaxing is a good thing--stress runs rampant in the NICU. In fact, my line for leaving the hospital after delivery and leaving the baby in the NICU is, "The smart man will take his wife home, have her take a nice long shower, hand her a drink of her favorite beverage, alcoholic or not, and give her a great massage!"  They usually giggle (they have been crying) and say OK, they will (and they do).  Touching is good--marriages go through troubled times when the baby is in the hospital with so many uncertainties.  The other thing we tell moms is, "Whenever the tears are flowing, your breasts may not, and that's OK.  It's due to stress, and it will get better when the stress goes away."  This applies to when they go home, whenever the baby gets an x-ray for something bad, septic workup, or when mom is unwell.  So if baby is having the usual ups and downs of 26 weekers, mom has an infection and is s/p hemorrhage, she has a lot of stress going on--and three other children to care for!  I don't know whether all of these things will help or work, but they won't hurt.  Also, point out to her, whatever happens, she is totally feeding her baby with breastmilk right now, which is VERY important for a baby so young and tiny, and that she is giving her baby the best start possible.  Good luck.
                                  Maureen Allen RN,BSN,IBCLC
                                  Lactation Consultant-NICU
                                  Brigham and Women's Hospital
                                  Boston, MA