First - thanks to all for your concern. This has been tough and it's nice to know that people care. :)
Felix has been responding well to his treatments, and even though he hates being hooked up to wires and tubes and such, he is pretty cheerful. I guess that means the asthma attack is past its worst. Essentially, being on the bike ride on Thursday morning (probably the cold and being strapped in and crying so hard against it) triggered an asthma attack that lasted till sometime last night after he'd been given a whole bunch of steroids for his lungs.
Brent stayed with Felix last night so I could go home and sleep (the cot in the hospital combined with all the beeping of various alarms wasn't going to give me nearly enough rest) and I feel much better today. And since Felix has responded well to the drugs, he's feeling much better too. He also got a bath today that he really enjoyed.
I missed the doctor's visit this morning, but Brent said that if Felix is still responding so well to everything he might be able to go home tomorrow morning. I'm not going to cross my fingers yet, but I'm guessing it'll be either tomorrow afternoon or the next morning. There is a light at the end of this tunnel...