atachi, im very sorry to hear about your friends grandfather...its an extremely unfortunate turn of events..
magick isnt a cure for illnesses...it cant remove them but it can help lower pain from it...
create a small circle of seasalt, and within it a picture of his grandfather, and a blue candle, with a flower next to it, one a day meditate by it for 15 minutes, focusing your energy your friends grandfather.
this is totally customizable, like the type of flower, a rune scribed on the candle, maybe you would want to read a prayer? find ways of making the spell stronger?
again, im reallu sorry about your friends father, i wish him all the best..