If your grandmother measures ingredients in pinches and smidgens, here's a way to record her recipes for posterity.
Get out the camcorders and film them making those recipes in person. Have them show you just how to do it, so even if they don't have measurements, you can zoom in and see that it's a "jelly glass full of water" added to the pot. Or you fold the dough in thirds, then flip it "like this."And then buy some of these.
At the very least, have a tape recorder with you so you can capture their voices telling about the food and when they first ate it, or relating that story that goes along with it. The more details you can get, the better. [Link]