When to release after URI treatment?

I captured a mother and her 3 kittens, had all 4 fixed, vaccinated, etc.  No issues with any except for the last fella, he has/had a URI.  The vet gave him Convenia, this was last Thursday. I still have him confined, this is the longest I have ever kept a male after surgery.  He is eating and having bowel movements.  He's also spitting and hissing up a storm!  AND crying to his mother who was already released with his siblings.  I do NOT want to stress him even further by such a long confinement, but I want him to be well enough to be released.  There is still a bit of a watery eye going on, the left eye.  Nose is looking pretty good and as I said, he is eating just fine.   Any help/feedback/opinions would be much appreciated!  

Any chance the vet can give an opinion? - maybe with a picture of his eye?   I think Covenia lasts up to 2 weeks, so you may need to keep him a bit longer, just to be safe.

Thank you for helping them all.  They're lives are vastly improved because of your work.

Thanks, Ondine, for your reply!  Hey, I'm in NJ, too, Middlesex.  The Vet said out of an abundance of caution keep him 10-14 days.  I just worry about the stress of the confinement, but I suppose that's still better than letting him go too soon if he isn't well enough.    Thank you again!

I imagine he will calm down some - once they are fixed, the hormones stop raging, so that will help.  By the time you release him, he may actually not be as feral.  Fingers crossed you both get through this period with sanity intact. 

You are about two hours from me.  Sadly, where I am, TNR is a constant stuggle.  The powers-that-be were dead set against it for decades.  Due to volunteers, however, that is turning around.  Grants were obtained and slowly, very slowly, the evidence is mounting up.

I am not aware of any place where there is complete concensus that TNR is the best approach.  If I find it, I am moving there!

I am going to zip-tie 2 of the tru-catch traps together, give him more room.  He's small, that should be enough space for a few more days.  IF I could give him ointment for his eyes that would help, but I cannot "handle" him - he's quite wild and I don't want to add restraining stress to the mix.  I'm putting lysine powder in with his food and I've found that does help those with eye issues.  

We had TNR support for years, then it was stopped for years - and finally people realized that was a mistake, a lot more cats, and now once again we have local support for it!   I HOPE it stays that way.  It has absolutely cut down on the number of cats on the streets.  Sadly, people will still just feed and not fix, but we do what we can.

Thanks for the help and support!  

The lysine is a good idea, as is giving him more room.

Glad to hear you have TNR support. It really does make a big difference.