He should be on some anticholinergic medications to both prevent painful bladder spasms and to help prevent bladder shrinkage. Just because the ditropan didn't work doesn't mean others shouldn't be tried -- some people may need a combination of meds to prevent spasms, control leaking, etc.
NEVER clean a collection bag with vinegar. Studies have shown that pseudomonas thrives in bags cleaned with vinegar. Instead, use a 10 percent bleach solution. Do two tap water rinses, swishing the water around for 15 seconds each. Then fill the bag 1/3 full with the 10 percent bleach solution and swish it around for 30 seconds. Drain and air dry without rinsing.
Why is he on antibiotics full time? The presence of bacteria in his urine alone is considered colonization and should not be treated with antibiotics. Only symptomatic UTIs should be treated -- i.e. bacteria and fever, flank pain, malaise, blood in the urine, elevated white count. Run a C&S on the first urine collected immediately after a new catheter has been put in so you're certain you're treating the bacteria that's present in his bladder and not just the bacteria colonized in the old catheter.
I'd really appreciate it if someone would post a link to the 'evidence-based research' advocating not changing indwelling catheters on a regular basis.
ETA: Are you sure the research you're talking about didn't show that there was no benefit to changing catheters at arbitrary fixed intervals -- i.e. every four weeks -- but should instead be changed as needed based on clinical symptoms [encrustations, leakage, etc.] and tailored to an individual's needs rather than actually advocating *no* cath changes? Someone who only skimmed this article might read the bullet point about no arbitrary cath changes and interpret it incorrectly to mean no changes at all.