How long cn it take to restore normal functionality after brain swelling due to viral encephalitis/meningitis? what are the chances of full recovery?

Good chance: Depending on the severity of the meningitis, I have found that most of my patients do very well, and have a full, or near full recovery. Occasionally, there are cases that leave behind scars that can lead to seizures, or brain injury. However, this is best answered by the neurologist or neurosurgeon that was involved with the specific case, since there can be many factors relating to outcome.