No - he may have physical issues even say pretty severe headaches of some sort (migraines, myofascial pain). Without access to his actual doctor visits can't really tell you what I would diagnose him with. What I'm very confident about is that arachnoid cyst means close to next to nothing. We see these things all the time on imaging. Because they are present in a lot of individuals when you scan people (say for headaches) then you find these things and people get worried because it looks frightening when people see their scans. However, multiple studies have shown it's an incidental findings and it's extremely rare that that the arachnoid cyst is the actual true cause of their symptoms - these type of cysts are present in about 1-5% of population and are symptomatic only about 5% of the time and when they're symptomatic it's thought to be mostly in children. For adults these essentially these are fluid filled sacks that build up over decades and are just sitting there basically doing nothing for someone to find them when they get scanned for another reason. Think of it like a lipoma or mole on your skin: yeah it's there but not doing anything bad So what happens is that surgical procedures to drain these things don't "work" as the cyst was not the cause of the symptoms in the first place (because stress is probably a bigger trigger for his headaches) and that when you drain them they come back because it's just a fluid filled sack. Could it have been in a really weird location which is rare for these thing where it was causing - maybe but I've seen enough of these cases thru the years where 90% of the time these things are done because the family presses some pliable neurosurgeon to do the drainage. It's interesting is it not that he had the surgery in 2014 and he was still having problems?