Samson is gone.
X-rays showed a tumor attached to the heart and possibly lung, slowly shutting off the trachea and one lung completely filled with fluid.
He came home Tuesday night and we hung out until this morning. On the way to the vet's, he went into respiratory failure. I had hoped to spare him any pain but couldn't. At least the pain didn't last long. He's in a much better place now and I know that we gave him a very good life.
I'll be back in a few days.