I am deeply sorry for your loss and hope that your family returns to good health quickly. I will pray for your family. It is terrible to be sick on vacation (we were a couple of weeks ago at WDW but nothing serious), and then to lose your father...................just terrible. Hang in there as time will heal those wounds.
As for associating this terrible event with WDW...............for a time you will, but I suspect you will get past it. My mother died in July of '96. She was sick with cancer and my wife and i had a 4th of July trip planned. She encouraged us to go. Needless to say, we got the call while at WDW that she had passed. Granted, she wasn't there with us, but I thought I'd never be able to view WDW the same again. In time I came to realize that things worked out the way that God had them planned and we do enjoy our Disney trips again.