[nonbel]

"Luck" just means we don't have enough information to say why so you use a statistical model instead. In the same way we treat winning a coin flip as due to luck but you could devise a situation where you know exactly what will happen given all the right parameters are known. In the past people called the same thing "god's will".

That said, it doesn't mean the cancer needed to be heavily influenced by any conscious choice/behavior made by your father.