Thanks all for the thoughts and prayers. We thought we were going to lose the guy, and he's bounced back. My mother found him incapacitated. Six more hours and he'd have been dead.
The scary thing is, they don't quite know what happened. They've changed diagnoses a few times, and just when they thought they were solid on one, my brother contradicted it, and they're back to square one. He started stiffening up, went to bed with a fever and tired, fell asleep and never woke up. My mom, who had driven to North Dakota from California, couldn't reach him, so she cut her trip short as a precaution. As she got closer to home and still couldn't reach him, she pressed on and found him half dead.
They got his kidneys up and running, and he was comatose for about a week. But he's out of it now, and seeming to be doing much better.
I appreciate the outpouring of love and support we received. My family got a wake up call about the nature of life. Hold your loved ones close because life can be weird out there...