Hawke and all,
Loss is a very private thing. We all do it in different ways. At least it sounds like you've all had a chance to be with your loved ones knowing the end was coming. My son, my only child, died very unexpectedly, all alone in his apartment and wasn't found until the next day when his fiance picked the lock on his door and found him.
Cherish the good memories and don't be afraid if you're grieving any "right" way. There is no right way for all. If you feel like crying, do it but don't think there's something wrong with you if you don't.
Talk to friends, write a letter to the loved one you lost and express your feelings of love, anger, frustration, loss, whatever you're feeling. Do it as many times as you feel you need to. But whatever you do, don't try to fit a mourning mood that someone else expects of you. "Jump starting" a mourning is not going to help you get over anything if you're not ready. Accepting the loss and being able to see into the future as it now is, is the most important.
Do what you can to return to a normal routine and just accept that there will be times you feel the loss more than at other times and understand that the feeling is okay, whatever it is. The last thing your loved ones want you to do is to waste your life grieving something you cannot change.
My best to you all and may this sad time bring you time to reflect on the best way to honor your loved one, by getting back to your own lives and living the best way you can as soon as you can.