Sometimes bad things happen to good people. There's no reasoning behind it that we can speak of, and having gone through this recently as well I know what you are going through.
Be with your family and take some time for yourself, you're always the great guy helping others out, now it's our turn to give back, to patiently wait and send positive thoughts to you and your family.
May he rest in peace, knowing you I am sure he was a wonderful person.