What Would You Do?

A friend of mine watches a baby that is 9 months old and only weighs 13 pounds. The baby has not gained any weight in 3 months. She will not take a bottle, no matter what is in it. She eats very little solid food. My friend is nursing her 13 month old, so she has plenty of milk. When my friend rocks the baby, she turns to nurse and she is certain that the baby would breastfeed from her. My friend has no problem with nursing this baby, but the mother is all weirded-out about that. And yet, she keeps working, even though her baby will not eat anything when she is away from her. I have my opinions -- no surprise there. But I'm just curious, what would you do?