Do your research. I'm not an expert, not even close, but a buddy of mine pushed his wife's curve way, way out. Maybe you can too.
She has stage 4 lung cancer, it's spread to her brain. If she gone to Stanford, like she wanted, they would have done whole brain radiation to try and blast the brain tumors. The problem with brain tumors is that there is that barrier that keeps bad stuff out of the brain and it only lets small stuff through, chemo tends to be large.
My buddy started researching and asking questions (he's business/sales but I think he's an engineer). The 5 year survival rate is less than 1% for stage 4 lung cancer. So he started asking doctors and hospitals "what's your 5 year survival rate". Everyone pointed him to national stats and he said "no, I know those numbers, what are yours?". El Camino Hospital publishes their numbers because they are much, much better: 15%. I know, 15% isn't great but it is a boat load better than under 1%.
So they went there. El Camino has a different approach to this sort of situation, they use some chemo (avastin maybe?) that is small celled and gets through the brain barrier. They also did pin point radiation.
The results: it's 2 years out, I think 2 years and 1 month, and my buddy's wife isn't fine but she's damn close. She's on an every 3 week chemo cycle, she typically gets 11 good days and 10 crappy-bad days. They both retired (I still pay his health insurance which is a big deal) and bought a travel trailer, do 2-5 days trips up and down California. They are fully aware that they are trying to cram all of their retirement into a few years and so far are doing a great job, their doctor loves it (apparently a lot of cancer patients sit on their butt, just waiting for the next chemo session).
If she had gone to Stanford, while the radiation would have likely wiped out the tumors, it also has this little side effect called dementia, happens very quickly. So this outcome is much, much better and it only happened because my buddy did his homework.
And one sort of cool thing happened: this all started before my company imploded and I gathered the team and said "I want to send Bob on vacation. We've only got so much runway left so if you don't want to use some of that money on Bob, I get it, I won't judge, I'll pay for the vacation myself." It was unanimous, they wanted the vacation to be from the team (I was so proud of them, that's the team I wanted). So we sent them back east to see the fall colors, they had a great time.
It's worth stating that I've watched my mother-in-law and my father die of cancer (and while my love for my dad is pretty obvious, I loved my mother-in-law as well, we got along great). The thing that I've learned is the second you know you have something that is life threatening do whatever you want to do RIGHT NOW. I pushed for the vacation thing for Bob because my mother-in-law didn't want to have friends over "until she was better". I deeply regret not just arranging to have all her friends come in. She died pretty quickly.
So I don't want to be morbid, or show any lack of hope, but there is the possibility that OP is in the best shape he's gonna be. So use that time to have some fun, build some memories, whatever you think is good. If you kick cancer's ass you'll have some memories to look back on, if you don't, your family will have some to hold onto. Do not listen to the doctors, they tend to be overly hopeful and give you a false sense of hope (I get it, it's kind of all they can do, but we would have liked a more realistic view. They let my mother-in-law think she was going back to work).
Good luck, cancer sucks.
Edit: explain that lots of patients don't live between chemo sessions and a typo.