Michelle,
My personal favorite was Campbells Tomato Soup. My husband would make it with about half to 2/3 of the can of water. It really soothed the savage beast my tongue turned into. Not sure if it was the sodium in the soup, the tomato or the fact that my husband found something that really did the trick for me and made a presentation every time he brought it to me. Jello pudding cups, popsicles, little individual servings of Blue Bell ice cream, sherbet... he had a never ending supply of cold smooth things that really helped.
Best to your mom,
Lisa