Just about a week after I brought him home, BoyCat is doing well. His behavior is just about back to normal, and he hasn't had any episodes of labored breathing. He vomited a couple of times on Monday, but that may be a side effect of one of his meds.
He has learned that my cell phone alarm going off means treats because he gets all his pills in pill pockets. The other cats have learned that the pill bottles being shaken means treats for them because well, I can't give treats just to him and not the others.
We go back to the cardiologist on Tuesday for more x-rays, bloodwork, and so on. I hope that the tests confirm that things are looking good, considering his condition. I've noticed that his jumping ability has actually improved; he had been having some trouble making it up on the bathroom counter on the first try before he had his attack, which may have been due to poor circulation affecting his back legs.
I realized I've never posted a photo of BoyCat. This is the best one I have (ignore the funky-colored devil eyes).