Kellie,
Given this mothers history of a massive bleed.  I think I would be looking at
possible Sheehan's syndrome as the cause of the let-down failure.  The
pituitary is very sensitive to blood volume loss and can infarct as a result
of the bleed.  She may not be producing any oxytocin.  When she is able to
pump a larger amount of milk, I wonder if it is just normal fullness rather
than the presence of a let-down.
 Oxytocin nasal spray may help.  Since there are other serious problems
involved in Sheehan's syndrome perhaps a referral to a good endocrinologist is
in order.
Marie Davis, RN, IBCLC