terrible news mate, I lost my gran to cancer, she brought me up from when I was born and its fair to say I was a grannys boy, she had bowel cancer in her 50s which she survived but was left with a colostomy bag and she had countless problems from that, then 10 years later she got leukemia which she fought hard for many years but in the end the countless bouts off chemo and everything else took its toll, she also had a major heart attack bought on my the treatment she was having to have, I loved my gran so much but after watching her suffer for so many years I did find peace when she passes away and I know she did aswell, death effects people in many different ways but I hope you and your family also find peace when your dad passes, it will be very upsetting obviously but its no life living the way many cancer sufferers live, I am very proud of my gran how she carried on the way she did, she was hard as nails and although she was in a lot of pain she just got on with life, an absolute inspiration she was, hopefully one day we will beat cancer, anyway all the best mate and stay strong for the old man