Hi Debi,
Mothers I have known with triplets have done it differently.  I think your
wisest council would be to "do your best".  It she could do 15 to 20 minutes
8 times a day it would be great, but her health and energy must be of major
concern too.  She may start out pumping as much as she feels up to and
gradually increase the frequency and duration.  If the babies are in the NICU
and she has to divide her time between self care and visiting and bonding to
them there, more than 8 times a day would be pretty super human.  You didn't
say how early the babies might be.  Hopefully it won't be too long before
somebody can start nursing.  She does need to keep pumping until EVERYBODY is
nursing.
Some mothers I know use a triplet rotation where they nurse 2 babies
simultaneously, each has one side to him/herself.  Then baby #3 gets both
sides.  Everybody gets shifted in a clockwise rotation for the next feeding
so the baby that was last now gets his own breast.  One mother began limiting
the feedings to 20 minutes after the babies were 6 weeks old, so she would
nurse the first 2 for 20 minutes, then baby #3 got 10 minutes on each side.
 So in 40 minutes she was done.  BUT she would nurse them again as soon as
they indicated the need, maybe 1 hr later, or whenever.  I don't see how this
triplet rotation can be any harder that her pumping after feedings.
Good luck Debi and especially to your doctor/mother friend.
Jane