Lisa,
This is purely anecdotal, but it is true.  My friend's son had
non-Hodgkin's lymphoma at age 6 while she was nursing her 9 month old
daughter.  My friend pumped and gave 6-8 oz. of her milk to her 6 year
old daily in his cereal throughout his hospitalization and treatment.  He
recovered and is now a healthy adult.  She believes he was the first kid
to survive that particular cancer, though I cannot validate that.  It
makes sense that human milk would be easier to digest when a child is on
chemo, and that the immunologic benefits would be important to a child
whose immune system is being subjected to the double whammy of leukemia
or lymphoma and chemo.
Assure your friend of our prayers for her son.
Catherine Watson Genna, IBCLC  NYC  [log in to unmask]