I agree with what most everyone else is saying.
If this were Jackson, I would probably just stay REALLY bland for a few weeks. No extra treats, no wet food, no raw, no dog kibble, nothin' but chicken, rice or potatoes like suggested. Kind of just to clean out their systems and see where it goes after maybe 2 weeks. I'm sure all the meds they're on can't be good for their tummies, either?
What about all those limited ingredient kibbles? Natural Balance offers one, and while it is grain-free, it's mostly potato, and not alot of meat. But maybe that's what they need right now. California Naturals is out there as well (even though the company was just bought out by P&G, it may be worth a shot?)
I'm sorry Sadie and Bentley are feeling ill.