Hi Michelle, I think that even when the liver is affected and there is no treatment, the prognosis can be dramatically variable. I don't think it is gloomy to recognise that you could be moving in to the phase where it is really important to gather happy moments, memories that you can hug to yourself later, photos of the good days. It is also important to keep saying the things in your heart - to leave no loving words unspoken and nothing to regret later. You mention that dad still looks well and so perhaps he will be with you for many months yet - I do hope so as a beautiful summer will give you lots of opportunities to do things as a family and store up those special times.
If not already considered, do ask the nurse about a referral to your local hospice (many offer day services, drop ins, massage & aromatherapy as well as counselling & emotional support for you and if needed later, the all-important specialist pain relief that hospitals sometimes struggle to manage well) or Macmillan nurses. Financial advice might be useful to dad - has he arranged his will, for example? And this may sound harsh but have you talked as a family about end of life care? In my experience, it is much easier to talk about this early on, long before you get to the stage where it would be frightening to the person who is ill ... staying at home, being in a hospice - some people have quite strong views and not necessarily the same ones as their closest family members.
Difficult times but perhaps not imminent - be strong