I don't know if I've ever met you my fellow Buddie but 3. and 4. have me greeting right now. All the best with whatever has to come. I hope it's early and curable and even if it turns out that it isn't, remember it's not the end, just the start of a new chapter and journey for your dad, you and the family. Stay strong.Also tell your dad he is a wonderful man for 3. regardless of how it feels now.
ETA: I hope that isn't stepping over the mark, but I felt compelled to write that more than anything else I've ever written on here.