Yes indeedy, that IF#1 goes right into the bloodstream and into the breast milk, and causes the wee-ones to have major poops & digestive disturbance (and even 'burny bottom' has been reported from the cayenne).
The most gentle (yet effective) of all 'laxative' herbals of which I'm aware is the Ayurvedic blend called Triphala. It's available in capsules at Mountain Rose.
However :::big fat sigh::: there's generally the typical 'warnings' for breastfeeding & pregnancy: "be sure to consult with your practitioner/physician" or worse yet "not for use during pregnancy or breastfeeding". I spent over an hour searching for any true evidence it could possibly cause harm and came up with a big fat zero. I also found several practitioners that recommended it for children that are dealing with constipation (one for infants even) - so I can't imagine there's any possibility of harm (except it will likely cause the baby to be a -hopefully smaller & gentler- poop factory, since it will go through to the breast milk, too). It shouldn't cause any 'digestive distress'.
You/she can read more about how these "typical warnings" come about here: //www.curezone.org/forums/fm.asp?i=1477065#i
If she decides to give it a try, have her start with just like IF#1 (one capsule with evening meal) and work up to what she needs before starting the IF#2.