It may be too late to help you on this emergency question but here is some
information. In general breastmilk from a Jewish women who is keeping
kosher would be prefered but in the case of threat to the health of the
child there is MUCH leaway in Jewish Law as there is an overriding
principle that a life threatening situation (and even a suspected one)
overrides all the commandments with very few exceptions. The father should
be asking this question of a competant rabbi to whom you can stress the
health risks of other nutritive alternatives for this baby.