Why does you friend need to stop lactation?
Some breast-feeding is good for the baby's health. In fact breast milk is the best for preventing infant illnesses. Breast-feeding is good for the mother's recovery and mental health as well.
If your friend has trouble doing the breast-feeding correctly, ask her to be patient. If necessary, she could go to see a nurse to get some advice. Pumping devises are available to relieve the situation. So please ask your friend to call her family doctor or nurse. He or she should be able to help.
Cheers!