When we are confronted with a potentially fatal diagnosis for ourselves or a loved one, we can find ourselves caught up in endless cycle of "why."
"Why is this happening now?"
"Why is God doing this to me?"
"Why didn't I see this coming?"
"Why didn't I (he/she) go to the doctor sooner?"
Recently, the analogy came to me that dealing with the diagnosis of a serious illness should be more like confronting a house on fire. If you arrive home to see your house in flames, you don't ask, "Why is my house burning?" You accept the fact your house is on fire, make sure everyone is safe and call the fire department. Later, if a neighbor or friend offers you a place to stay overnight, you graciously accept.
From my experiences being my wife's caregiver, this is a good way to deal with your own or a loved one's serious illness. First, don't get stuck in questioning why this is happening to you. Instead, accept the reality of what you're confronting! Next, get the best medical help available to treat the illness. Finally, accept your family and neighbors' offers to help or ask for what you need.
Accepting what is and taking care of yourself and your loved ones are the two best bits of advice I can offer.