Hello Denise-
I strongly suggest she NOT make breastfeeding an issue here!  Focus on
the individual child's personality and sense of security..  Will such a
seperation from her primary cagegiver be threatening to her?  Why can't
dad come to HER rather than making her take the brunt of the
visitation?  Keep breastfeeding out of it- in fact it has nothing to do
with it.  It is about what will be most comfortable and secure for this
(no doubt already affected by the divorce) four year old child.

Good luck. Sue Jacoby LLLL and  IBCLC