My thoughts are with you and your family hang in there. Cancer is bad in my family I've had 2 immediate family members die, and my uncle is currently battling it.
The biggest thing I can tell you is not to let it drag you down, the most important thing for you and your dad is to enjoy life as much as possible. My uncle chose not to do a bunch of chemo and surguries and to just enjoy life. This way if things didn't go well, he didn't miss out on what time he had b/c his was in class 4 there's 5 they use I think he told me. So far since he's found out it's been over 2 years now and he's still looking good like he'll be fine for 5 more years. So high spirits and positive energy can make all the difference in his battle and recovery. So keep being positive and hang in there!! Hope works miracles! He needs yours more than his, b/c if surrounding people aren't it's that much harder for him. I know how you feel, just keep doing what your doing. Good luck and my prayers are with your dad.