This was far more than just random chance. It's clear as day that quality of medical care makes a difference in outcomes, right? I have sent this discussion to the relatives in question so forgive me if I get the exact details wrong. But the median survival time for glioblastoma is fourteen months, and they were quite a while into that. Their original doctors were recommending palliative care (giving up on further medical treatment) with a couple of months expected survival.
My relatives live in a small city not known for its quality of medical care. They found the very best neurosurgeon in the country for glioblastoma and transferred him over with some difficulty. They learned that the initial surgeries were not done to a high quality or possibly even slightly botched - and the new surgeon was able to perform additional surgeries that were able to remove a significant amount of the tumour (and did follow-up surgeries later on). Of course this would extend a patient's lifespan!
The ketogenic diet now seems to be becoming a standard recommendation for glioblastoma treatment. There are TON of studies now. Here are a few more more. [1] [2] [3] Note the dates on these studies (2017-2018). Back when they looked at this, this was absolutely bleeding-edge stuff. Of course going to the cutting edge of the research, speaking to professors and using your brain to figure out what might help in your case will improve outcomes!
Regarding clinical trials, one can read up on / sign up for trials of treatments at different stages of the drug research pipeline. As the modelling spreadsheet in the link above shows, between 1-in-10 and 1-in-2 of these trials will result in FDA-approved treatments that will hit the market between 2 and 10 years from now. If your current expected survival time is in months, it is statistically worth implementing as many of these as possible, because at least one of them will probably work, and you don't have the time to wait for the FDA! You don't really care which one as, like you say, your sample size is N=1.
I shared this in the hope that some of the smart people on this forum would read this and know that this is something you may be able to do. We are engineers and scientists. We can read studies and think critically. We can spend a ton of time absorbing specialised information about the N=1 case that matters to us. Death comes for everyone and the above may not make a difference in many cases. But it turns out that sometimes it does! Don't treat medical care like a black box.
[1] https://www.practiceupdate.com/content/sno-2018-clinical-tri...
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834833/
[3] https://www.sciencedirect.com/science/article/pii/S104084281...