I think the best thing for her to do is get some labs done to have her iron serum, ferritin, iron saturation and maybe even b12 checked. Assuming that she is anemic and it is caused by her vegan lifestyle there are some things she can do. Being low on iron isn't a good thing, fixable yes but something you might want to consult with a Dr. about so that he can keep track of things. It can get to a point where blood transfusions are required when it goes untreated and your hemoglobin/crit become effected. There are many different types of iron out there and worth taking a look into. Take this serious and take her to the Dr. in the meantime:
Lentils, soybeans, tofu, tempeh, lima beans, guinoa, fortified cereals, brown rice, oatmeal, pumpkin seeds, squash, pine, pistachio, sunflower, cashews, unhulled sesame, tomato sauce, swiss chard, collard greens, unsulphured blackstrap molasses, and prune juice.
When you cook use a cast iron pan.
Eat your iron with vitamin C. Avoid coffee and tea they will also decrease absorption. There is only a certain amount of iron that is going to be absorbed when consuming larger amounts of iron anyways, our body only takes so much and gets rid of the rest so I guess in theory she will absorb more in littler amounts. Our bodies can only take so much iron at once.