hi K.,
so sorry to hear about your friend. i hope everything goes well for her. about the 4 month old, though, had he ever had a bottle before? and is she the only one giving the bottles? it could be that he's refusing because it's so different, even after a month. obviously she has to persist, though, so if it is the bottle, then i would recommend looking at which kind of bottle she's using (we had great luck with avent switching between breast and bottle), and who's feeding him. sometimes they are less likely or less happy taking a bottle from mom when they are used to the breast from mom. if it's not a bottle issue, it couldn't hurt to switch formulas. i would recommend enfamil lipil, or an off brand like it. it has more dha and ara (which are the ingredients in breast milk that help brain and eye development) than any other kind. we used it when i needed to supplement, then found that target had a generic that had the same amount of dha and ara, for about half the cost! i think walmart has a brand as well. i hope that i have been of some help, and i'm praying for your friend!
J.