It amazes me that he can sometimes shoot distant enemies with semi-accuracy but fail to notice a huge jumpable gap ahead of him.
HL2 is actually a good game for gauging how good/bad his eyesight actually is. Mainly because its a lot cleaner and less frantic than Call of Duty and other newer games.
He doesn't seem to be squinting either.
When its in Call of Duty it doesn't seem to be an issue of aiming, but rather with timing/actual precision.
He completely misses environmental details. He seems to miss sound queues that are very prominent in HL2 like the health/charge sounds or gravity gun charge/empty sounds very frequently but he does rarely catch them and comment on them. You can notice he's missing them because he does stuff that is "wrong" when he misses them.
It mostly seems that he's either no paying attention/not actually immersed in the game or is more focused on chat. But having seen him play driving games once or twice I'm guessing he's just not actually immersed in the game.
You can see it with weapon choice as well because he's running around with the crossbow at full ammo and only uses it when he's really, really stuck. He'll just use the SMG 95% of the time.
You can also notice when he approaches a problem he looks at almost entirely one dimensionally. I rarely see him look around from different perspectives when he sees a problem. He sees the problem, but rather than try to proactively find a solution he'll just throw random shit at it until it works.
When he's near the prison area there are two different occasions where he just walks straight into a situation you'd expect most people being aware that it'd require jumping or sprinting. He slows down before, because he often recognizes there is a gap, but he doesn't think to look from an angle to see how big the gap actually is.
I guess he's the guy you go to the movies with to see something serious who completely misses every major plot point and has no idea what the movie was about.
He does seem to genuinely like the game though. I'm still amazed that he only played it until he got the gravity gun and then quit it (for whatever good excuse there was to do that back when he played it)
The thing that pisses me off the most is that he still hasn't figured out you can fire the gravity gun with nothing in it if you just primary fire it close to something. Instead he stops and picks up each object to move it out of the way.