Cancer is a disease which needs to be tackled with understanding and comfort. It is a situation where your grandfather needs your warmth and that special touch to make him feel better as the medicines cannot work this way. My friend told me about
http://www.dearcancer.org/ where cancer patients can share about them, what they feel, their thoughts, their experience and their problems related to it. I think this will help your grandfather to be more relaxed and write and share the things he is concerned about.