Mom-coon made it back twice last night and retrieved two of her young - both of the females. I sat near our kitchen window in the dark until 4 AM and saw her make the snatch both times. Her new nest must be some distance away, as it took her about 90 minutes round trip. I surmise that she spent the rest of the night foraging since the male baby was still there this morning.
Everything I found via Google indicated that if we could keep him warm, hydrated and fed for the day she may very well retrieve him tonight. According to the sources she won't try during daylight.
So my partner and I made the trip out to a local pet store and found something called Kitten Milk Replacement. Normal cows milk has lactose, which does not agree with young raccoon tummies. He's taken two feedings so far, and seems to like the stuff.
Tonight I will set him back by the tree and see if his mother will come get him. If not, we'll take a trip to Boulder on Sunday to deliver him to professionals.
If anyone is interested, here are the links I've been using as sources today:
Edit - 12:30 AM June 3rd: I think we were successful at re-uniting him with his mother tonight. I missed the snatch, but he was gone as of 12:20 AM. Funny how one can become so attached to something for which one gave care - even as short a time as it was.
Fair hunting little brother. Perhaps someday you will cross my yard at night while I stand outside for air and you will -- for a moment -- gaze back and wonder. But I really hope you scoot your butt into the shadows and play it safe.