Sorry to hear about his passing garyfl.
Just to give you another perspective on when we lose loved ones:
I've lost grandparents etc in the past and like many others believed that was the end, but I no longer believe this.
I'm not speaking in a religious sense, since many of the original messages in many religions have been distorted and twisted over time for other means, but in terms of us all being more than the physical bodies we've been led to believe that's all we are.
Death is not the end but a transition of conciousness, from this very physical and dense place we currently call 'life' onwards to much, much more.
I'd imagine he's looking at you all right now wondering what all the fuss is about and willing you to get back to being busy living your lives and experienceing all it has to offer; you'll see him again, and in the meantime, know he's looking out for you.
Whether you believe this or not right now isn't really important but speaking from personal experience, it can be comforting to think of it all in this way.
Keep your chin up mate, and as others have said, don't feel bad about letting anything out as the worst you can do is bottle it all up.
Don't worry too much about the kids, they often handle this far better than the adults and on some level, seem to know it's not the end like most of us adults have been led to believe.