So sorry to hear this batgirl, I had a friend....Well more like a coworker< martin, with pancreatic cancer......We were quite close for work mates...He too was given 18 months....But alas his body could only hold up for 3-4 months.
For daddy I suggest living every moment to the fullest...All the rules are off...Run up the visa, do everything you've always wanted...But make sure all the other details are taken care of...That is if he is capable of doing this...No sense to leave this to the family as this time will be very difficult enough as it is.
For the rest of the family..........Enjoy every moment, take pics to concrete the memories, say everything you always wanted to say, now!, live and laugh..............And for goodness sake everyone do not wait until retirement to "do what you always wanted to do". Life doesn't get better by itself, it needs a little push.
Love and blessings your way :)