Sue,
I know this is not what you asked for, but why would this mother want to
become pregnant again NOW?  I know lots of people have timetables in their
heads about how to space their families.  But as each child presents himself,
sometimes we must rethink our plans.  Does she realize that pregnancy, new
baby will usually cause the older one to regress.  I know we should meet the
mom wherever she is in her life, but is she ready for this?  Maybe she could
handle it.
Of course, she could look for ways to encourage this boy to eat and even to
bf less.  I am currently reading Huggins & Ziedrich " The Nursing Mother's
Guide to Weaning" - this mom may find this helpful.  Could she wait a little
longer til this child needed her a little less?

Laurie Wheeler
"Life is what happens while we are busy making other plans."