I've been through this...twice. Most recently when my mother in law passed away in November and my wife was at the hospital every day from October 28 to November 14 when her mom passed. I also have two boys.

A few pieces of advice:

• You need to give your wife the time she needs. No doubt she has a ton of guilt being away from you and the boys. Support her.
• Tell your kids the truth. Now. Especially your four year old. Kids know when something is wrong.
• How do you not know how to raise 2 boys? Huge issue - you need to figure that out fast. Here's a hint - the currency of children is time. Give them your time and undivided attention.
• Use this time to get to know your kids, spend time with them, love on them. You won't regret it later.