as one who has had that same problem all her life, i can make a few
suggestions, although the process may be difficult, because children need
fat in their diets.

monounsaturated oils like extra virgin olive oil
nuts and seeds, including nut and seed butters that can be spread onto
bread or crackers - if she is not allergic
avocados
olives

i don't know if there are any canned supplements without dairy in them -
i've looked all over the place for myself and haven't found any.

zenzele