We tried.
I found a vet, we got him there. It was an adrenal tumor, as I had guessed. Alas, he'd gone so far so fast, he was untreatable. He was past medicating. They offered to try to get him to a point that they could operate, but told me flat out that the chances of him recovering enough were very slim. He would need to endure weeks of invasive procedures with a very small chance of success at the end. And if they did get him to the operating table, his right gland didn't look so hot either.
I let him go. It felt like Jiro all over again.
I asked how it happened. It came so fast. The first time I noticed anything out of the ordinary was less than a week ago. The vet told me it's not unheard of, particularly in cats and ferrets. He wanted to hide that he felt poorly, so he did until he had no strength left.
Yeah. So, have some Frankie being a knot of adorable.