However, the patient never would known about it because it wouldn't have been on the list of "approved therapies", so the doctor never would have suggested it.
The article dances around it, but for this particular cancer, proton beam therapy has little evidence supporting it. The current treatment guidelines like NCCN list a number of evidence-based therapies for first line, second line and subsequent line treatments. Proton beam thereapy is a "hail mary" and universal healthcare systems are less expensive than the US because they don't pay for "hail marys".
So in places like Canada (whose patients, it's important to note, need to travel to the US because there are no proton beam centers) the doctor wouldn't have even considered it as a treatment option in this case.