Captain reported the #2 main brake was never reactivated after corrective action and removal of an MEL. This was discovered after landing at destination airport.

Narrative

There are multiple issues that occurred on the flight all impacting safety. Rather than file multiple reports include them all in one. As a background the flight crew arrived after a minimum rest delayed overnight that resulted in a XA:45 AM hotel arrival after a stressful duty day 10 minutes shy of max legal duty limit. both flight crew members or fit to fly; however I'm going to state that fit to fly and well rested are two entirely different things. As a side note this was a crew base with an opportunity to re crew. The first item of consideration is that printed with the release was a page noting that we are not authorized to fly the Runway XX RNAV visual in ZZZ. This is in contradiction to the email dated Date 0; which authorizes us to shoot the approach. It takes time; effort; and concentration to coordinate and come up with a true legitimate answer in regards to our flight operation authorizations which seem to change frequently and that are not consolidated in one spot but spread over many many documents. A side note on this point is that the ACARS also generated a warning as we were descending towards the high workload airport in the mountains which told us that again we are not authorized to use the RNAV V XX. The weather was marginal with a wet runway and wind 9 kts. Essentially right down Runway XX. Clearly XX was favored. The second safety concern involves an MEL item. Out of diligence I always trace back in the logbook to see what trends the aircraft might have had or things that may have previously been problematic. This aircraft had been written up for a leaking hydraulic line On the number 2 brake. It had previously been deferred which involves an additional anti skid deferral and an aircraft landing capability downgrade. Prior to us excepting the aircraft it had been repaired signed off and returned to service with a clean slate and no deferrals. It had additionally been written up since that time for a discrepancy between the number one and number two brake temperatures. That was also signed off and Operations checked good. After landing in ZZZ during taxi the number one brake temp Reached around 330 degrees; number two was 30 degrees and three and four were fairly equal at around 270 degrees. That discrepancy requires a write up per AOM volume two. When Maintenance arrived It was discovered that the number 2 brake Had never been hydraulically reactivated. The Forward line was unplugged taped off and safety wired together essentially adjacent. we flew an airplane with a deactivated brake with no knowledge of that or consideration for the performance into a mountainous airport on a wet runway. Maintenance in ZZZ reconnected the line and we continued on our trip. Clearly this is the item that could've been caught on preflight however I will say that the manner in which this was wired together would make it very difficult to catch; along with the fact that we had multiple other issues which required maintenance prior to departing such as loose fasteners etc. The workload generated with these combined distractions and after a very short night. There's no way other to say it then it is an incredible amount of distraction and attention diverted from the task at hand.