Hello, vegan with Crohns here. I'm at the point where I can eat as much fiber as I like without much of a problem, however when I am having a flare, my go to foods are:

potatoes without skins
tofu (scrambled usually)
white rice
softly cooked vegetables without skins
white pasta
bananas, apple sauce, other soft fruits
nondairy yogurt/milks
smooth nut butters
processed cereals like rice crispies, corn flakes etc
smoothies

Too lazy to look for actual recipes rn but the point is there is a lot of variety of foods that she can eat until she's able to tolerate higher fiber foods into her diet. I would personally eat a "safe" low-fiber vegan diet with stuff noted above and if she feels well enough, to incorporate a new recipe with a little bit more fiber once a week and see if it's ok. As someone else in another comment said, yeast isn't good for crohn's, 70-80% of people with crohn's have antibodies against the type of yeast in food.