Hello, new forum user here, looking for some general input from people in a similar position, if thats ok. 

My dad is 63, and was diagnosed with Stage 4 NSCLC in September, which has spread to his lymph and adrenal glands. Due to other existing medical conditions, he was not eligible for chemotherapy, but did have some radiotherapy to try shrink tumours which were pressing on his windpipe. He has an internal defibrilator for his heart, and so we've been told that if it fails, then he wont be resuscitated. 

My dad wont tell us what the expectancy is for his diagnosis, although my mum works in a cancer ward and so has a vague idea that it is within months more than anything else. He was admitted to hospital with pleurisy in October and then released, but then began taking dizzy spells which culminated in him collapsing coming out of the passenger side of his car, where he cracked a rib and injured his face, hands and legs and he couldn't move, this generated another hospital stay, which was extended further as he caught E. Coli whilst there. He's now back home again. 

I'm struggling with his diagnosis as I don't have any straight answers really. All I know is that we are looking at months rather than anything else, however, he has been experiencing confusion in the last few weeks, where he's been reminiscing about the past and completely misremembering things, and he has been telling me that his cancer is in remission, the doctors are astonished, and will be writing papers on him this time next year. He can barely walk the length of the room, but has bought an exercise bike and has been telling me he is going to cycle a 'wee 5 or 10 miles' on it every night. 

He's also experiencing mood swings than can change in the blink of an eye, turning him from a laid back, relaxed guy, into someone who gives one word answers and rolls his eyes when you try to talk to him. There's some emotionally charged conversations as well, my mum told him she's struggling with the situation and his response was "oh yeah I can see how YOU'VE got it bad!"

I don't feel like I can talk to him about any of this, firstly, I don't want to say anything to bring him down, but I'm scared and worried. I'm his only daughter, and we're relatively close. I'm currently signed off from work with stress due to the situation and am trying to use that time to spend time with him but it's exhausting emotionally, as he sounds so convincing when he says things are going well that I want to believe him, but my head reminds me that the odds are against us. 

Does anyone have any tips on just how to get by? Has anyone else been through a similar diagnosis? What kind of timescales did you face? How did you cope?