I didn't want to leave your post unanswered. 💐
Firstly, every case is different so please don't take my post as any indication of what will happen to your DM, but I know how you're feeling. Secondly, I'm not on the UK mainland so medical care works slightly differently, but they follow UK guidelines etc.
I am going through a similar situation with my own DM(73). In her case it is pancreatic cancer picked up on a CT scan early in September after months of back and stomach pain, sickness symptoms etc all being put down to other causes such as possible diabetes, stomach infection, the hip replacement she's been waiting several years for etc. The scan showed a 5cm mass in her pancreas plus several smaller tumours in surrounding organs. So it was already at stage 4. Mum was given the news by her GP who asked her to go in the same day she received the results and urgently referred her to oncology. We finally saw an oncologist last week after a 4 week wait. She has already been under the care of the palliative care home visit team for the past 2/3 weeks after having to take her to A & E twice for dehydration and pain management.
Radiotherapy and aggressive chemo aren't options. Radiotherapy is only used if the cancer is in one area. Oncologist also said my Mum is too weak for the aggressive chemo which has about an 80% success rate. Her body just wouldn't cope with it.
Mum was offered but has decided this week not to go ahead with the less invasive gemcitabine chemo. It would only have a 30/40% chance of working and would add a month or two at best. The list of side effects is hideous and numerous.
They have decided against a biopsy as blood test confirmed cancer by 96%, CT scan showed them enough and they don't want her to have to undergo needless procedures.
We are now under the local palliative care team who check in several times a week and have got her pain and symptoms under control. She has even managed to eat again, so we just want to make her final months as comfort at home for as long as possible. She currently feels the best she has in months.
The oncologist can't give us an exact date on how long she has. 6-9 months at the very best but they don't know how long the cancer has been at stage 4. The average life expectancy is 3/4 months untreated for Mum's particular cancer type.
He also discussed a DNR with us, which Mum has agreed too and is now in place.
Just to prove every case is different. My friend's Mum had a cancer diagnosis 2 years ago, she responded well to the chemo and it gave her Mum a new lease of life. My friend said “It feels strange to say it, but cancer was the best thing that ever happened to Mum as she's finally started to put herself first”.
There are lots of cancer support groups in person and online. At the moment I'm just sticking to online but your local oncology team should be able to put you in touch or you can just google those in your area.
I'm lucky that my employer has been really understanding and has allowed me to drop my hours to spend extra time with Mum and let me stay away from public facing duties on the days it just all feels a bit too much.