New cagemate for sick rat?

Question
QUESTION: My rat Merlin died suddenly a few days ago (he was only 14 months old) and I can't decide whether to get a new cagemate for my remaining rat, Jack (also a 14-month-old male).  Both of them were from a pet store, and both of them have had problems throughout their lives with frequent sneezing and porphyrin and occasional grunting/hooting.  (A vet put them on antibiotics, but it hasn't seemed to help much.)  Normally, I'd try to find Jack a new cagemate right away so that he wouldn't get lonely, but here are my worries:

1. Jack is still sneezing/grumbling a lot, although he's still active, not acting like Merlin did right at the end (hunched back, walking slowly, resting his head on the ground, labored breathing).  If he has the same problem that killed Merlin (I'm tearing up typing that), then he might die soon, too, leaving the new rat without a cagemate.

2. If Jack is contagious, he might make the new rat sick.

3. Both of the rats would be unaltered males, and Jack's pretty small for his age.  Would the new male pick on him?

Do you think I should get a new cagemate right away, or wait a while to see if Jack's symptoms get worse?  Or not get a new cagemate at all?  I just want Jack to be happy.  Thank you for your advice.

ANSWER: Hi Laura

I would get him a new friend, but get two instead of 1. This can break the cycle. Always keep an odd number of rats to avoid a situation like this.

However, Jack needs to improve more if he is infected still and not suffering from lung disease such as scarring that will make him appear like he has active infection but its not. However, I am convinced he still needs treatment only a change in antibiotics.  What kind of medication was he given?

---------- FOLLOW-UP ----------

QUESTION: Thank you for the reply.  Jack and Merlin were both put on Baytril several months ago, but after they'd gone through the full course I didn't see much improvement-- less sneezing, but the snuffling/grumbling and congested noises were the same.

This morning I got Jack a vet appointment in case he is still infected, but the appointment is a week and a half away.  (My vet is the Cornell Vet Hospital, which is excellent, but always very booked up.)  Would it be okay for him to be a lone rat until then, or do you think he needs a companion right away?  (He's been alone for one week so far.)

Answer
Yes he should be ok. You can still go and get the new rats but keep them in another room so Jack doesnt get upset knowing they are there plus they should be quarantined anyhow before introductions.

Meantime, he will see the vet and get more medications. Just pay lots of attention to him, he should do just fine.