To an individual who is suffering a terminal illness, I would either send them an Inspirational card or book.,or better yet send them a Humorous card or a book aimed at laughter. If they are no longer able to read any lengthy material. One of above mentioned cards and maybe you could send a short note on parchment that reads something like this: My thoughts, strengths, love and prayers are always with you. Sincerely, (your name). I have lost a lot of friends and loved ones over time. Both my parents passed away seven days apart. My Mother May 1st, my Father May 7th. Not one person even expressed via mail, telephone, or card any concern for my loss and hurt. It would have been nice to have heard from anybody. I am always sorry to hear of the suffering some people go through. Express your love now! It means everything. Take Care.