She might find it easier to cut back on his bfs rather than wean him cold turkey. For eg, if she's still bfing him during the night, cutting out those nights bfs can really put you in a whole different headspace during the day (not to mention you get a bit more rest if someone else takes over at night!). It isn't easy, but generally doesn't take very long. 'Bbs are asleep at night time' worked for us, replacing with a cup.

If she hasn't night weaned, I'd suggest she try that first. Then she can see how she feels once she's getting a bit more rest (hopefully) or at least not feeling like she's feeding around the clock. It made a big difference to me (although I wasn't pg) and I was happy to keep bfing knowing I had that 'space'. There are some other threads on here about night weaning too, where you'll find some useful information.