Hi, I had breast cancer 3 years ago and had a mastectomy. I was cancer free afterwards. I have experience with my own dad being difficult and having a disease that would contribute to his death (cirrhosis). He stressed me so much with his demands on me. My dad was always very strict so contradicting him on anything was a no no. The day before he died he was hassling me from his hospital bed about looking into ppi, which he'd never had but wouldn't listen. Its very difficult to deal with a crotchety parent, I know. My only advice, and I hope it helps even in a small way, is try to keep patient (easy to say!). If you find yourself getting angry, and I did, walk away for a few minutes and calm yourself, you cant control other people but you can try to control your reactions, and I found this VERY difficult, I would go home and cry. Channel the negative feelings into something positive, whatever that is for you, your hobby, exercise etc. The one thing I would say to try not to do is allow you and your dad to fall out permanently, obviously I don't know what you were arguing about, and I don't need to, but most things can be gotten past but it can take effort. Make the first move and call him, if you can. Keep in touch any way you can (my dad and technology didn't agree) and don't lose what time you have left. Lastly, a biggie, if YOU need help there plenty of organisations you can contact and you can talk to someone who isn't involved and work through your feelings, get help if you need it. I had counselling before my dad passed and grief counselling afterwards, it helps. Good luck. Keep chatting on here too, other people have the same experiences, or similar anyway, and can help. I hope my prattling has helped a little.

Thanks for you reply, you wouldn't have the names of those organisations handy would you ?

McMilllan is a cancer specific organisation and can offer all kinds of help. For mental health try Mind, Insight or Google mental health help. Your doctor can also provide names of local organisations you can self refer to. In my experience its definitely worth trying, even just for someone to vent to, talk to, you're bound to have all kinds of feelings and it helps to talk. I was unsure at first but did find it helpful.

My long term partners mother passed away from pancreatic cancer 3 years ago. They didn't have a good relationship he spent most of his childhood in children's homes . And ended up having not much of a childhood . She had other children after him who she cared for better as she was older when she had them and more mature . She was quite young when she had my partner . But he did visit her in the hospice a few times and they made their peace . Privately before she passed away . He didn't attend her funeral , neither did I or out children as she wasn't involved in their life's . He was judged for not attending but it was the right thing for him at the end  of the day . Do what you feel is right , don't listen to anybody else . Think how you will feel when he is no longer around and if there's anything you will regret then make a decision . 
good luck  x