I cannot understand this sort of relationship between doctor and
patient, though I know it is the rule rather than the exception.  As I
always understood it, the doctor, *based on the best available
evidence*, advises, the patient decides.  I can be told that my high
blood pressure (hypothetical, I don't have high blood pressure, though
more stories such as this are bound to increase it), untreated will take
x years off my life, or leave me with a brain hemorrhage, incapacitated
for years, or...  The doctor should also tell me that the medication,
which, presumably I will have to take for the rest of my life, may cause
electrolyte abnormalities, or heart failure or make my asthma worse (all
potentially fatal) or cause impotence (not potentially fatal, but you
know how men are).  If I decide not to take the medication, given that
information, there is nothing the doctor has to say about it.  He might
reaffirm his belief that I take the medication, if, next visit my blood
pressure is high, but there is nothing he can do to make me take
medication, even if my blood pressure is 220/150.  The same with smoking
(I don't smoke either) or getting my cholesterol checked or anything
else.

Given the facts here, most mothers, I think, would opt to continue
breastfeeding, especially since the mastitis (if that's what she had)
would get better faster with continued nursing.  I think the physician
can talk to the mother in such a way as to encourage her continuing, or
in many cases give the same information and convince her to stop.