Talked to the vet this morning.  He said Max is doing well, and he was going to take the catheter out this afternoon and see how he did.   He said there was an infection that started the blockage, and about 1/3 of this type are started  by certain brands of food.   I hadn't fed any he mentioned, but I did buy an odd one about 6 weeks ago, so that is likely what started it.  He suggested a brand he feeds (not an expensive one)  so I'll use that one.

We just got home.  He sure was thirsty  The good news is, he pee'd!  And more good news was, when I went to pay the bill there was a mysterious $50 discount showing and the lady at the desk had no idea what it was for, so she went into the account and read a note, and all she would say is "Doctor Goza knows what it's for",  but she wouldn't tell me more than that.  Cool--I can handle a discount  And Mr. Keeper Boyfriend had given me $100 toward the bill to begin with, so it cost me nothing  Whew.  I needed that.

Yeah- a cloud with a silver lining.  Sounds like good news all around.  Hope Max is resting comfortably, except for many potty breaks.