It is terrifying that’s for sure. I would just say, make sure you are given as much information as possible on the type of cancer your Dad has, the treatments that are available and the side effects Dad might have from the treatment. There is a lot of support for patient and families do try not to worry too much, there is always someone who will be able to answer your questions. It’s normal to feel panicky at first but there is a lot of support out there for you