just got a phonecall from mum, dad had woken up for a second before his morphine injection, she held the phone to his ear and i told him i loved him and my goodbyes, god sake it is the hardest thing ever had had to do
I know exactly what you're going through, as the same thing happened with my Dad, except that he was a victim of kidney cancer. We too thought he'd beaten it, only for a check-up 18 months later to show that it had come back and spread to his lymph nodes.
It was and is the hardest thing I've ever had to deal with - watching a fit, active bloke (he hadn't smoked since the late 1960s, watched what he ate and was an avid cyclist, both in his youth and middle age) be turned into a bedridden shell of a man, so doped up on morphine he barely knew what day it was.
The final time I saw him alive will be seared on my memory until the day I myself die. He was in and out of consciousness and it was obvious the end was near - I just took hold of his hand, kissed him on the forehead, looked him straight in the eye and said "I love you to bits Dad and I always will". I know he heard me because he looked at me and smiled and with what little strength he had, squeezed my hand.
Believe me, you will find a way to cope that works for you and you may possibly find strength of character you didn't know you had. It was only when I came to write my eulogy for the funeral that I cried, but it let out a lot of grief and enabled me to be a rock for my Mum, Nana and Auntie at the actual funeral itself.
Another thing we did which helped all those present was to have a 'close family only' wake after the official wake - Dad had a wicked sense of humour and wouldn't have wanted a load of weeping and wailing, so we reminisced about all the laughs we'd had with him over the years. The drink was flowing, the tears were those of laughter and I vaguely remember my brother nipping down the chip shop and coming back with cod & chips for everybody - it was great therapy and numbed the pain for all concerned.
All I can say to you is there is no right or wrong way to handle something like this - do whatever works for you. Stay strong for those around you, but don't feel ashamed if your emotions get the better of you. Talk - don't bottle anything up.