Get her a little bottle of glycerin at the drugstore. Pour a few drops on the blood and let it sit overnight, then wash the item. This works very well on tablecloths and napkins, too. I used to keep a bottle in the top drawer of my buffet, and if someone spilled meat juice or wine on the tablecloth, I'd immediately pour it on the spot. If it's a large spot, just rub it around with your fingers. It works every time. Peroxide also usually works well, but be careful that it doesn't damage the fabric.