Answer:
possibly; let me give you a little insight. The chances of CTE from a concussion is rather low but having signs of CTE from playing is a high chance in long term. (something like 80-90% of the players had signs or clear symptoms) in a couple of studies of former players. With your boyfriend it could be many things and not CTE (unless it was repetitive. A single concussion isn't enough. You have a higher chance of developing CTE in contacts sports such as boxing or any of the other fighting arts.) Just keep an eye on him and try to not let the thought control your thoughts. Has his family or himself been checked for other possible developments? This could be related to simple autism. Early-onset isn't always noticeable even into later life. (I have PDD and never found out until i was 19 and went through a few tests it wasn't entirely apparent)
Step-by-step explanation:
CTE is very loose laying term when it comes to not being diagnosed with it (which well you can't..). While CTE isn't necessarily common from concussions it can form if the said subject has had extremely bad repetitive hits. Short term memory loss, depression and the other cognitive functions that can be affected.
Also it has been found in other ways than an autopsy but not in humans or at least majorly public. I sort of explained that in the answer, it's not worth going into detail as a lot of it was rodent based in labs with blunt force equivalents and studies regarding their behavior. (make sense?)
in short concussions can't really be related to CTE but that doesn't mean it isn't out of the spectrum. I would keep an eye on him for a month or so and just take notes of similar diseases that deteriorate brain functionalities.
Now for the part you may or may not want to hear this is a major blank zone. CTE on it's own isn't entirely fatal. There is not enough and simply just is NOT enough data to make any kind of statement here. CTE can be related to many diseases but doesn't necessarily mimic other diseases. The fatal parts of CTE come from your brain dying, slowly but not painfully. You wouldn't exactly notice until late stages lets say 20-40 years down the line it could progress to the point that you lose normal bodily functions. Your ability to swallow down the right tube and not having the ability to say it alongside not having control to get it out of your system with a cough or such. It's sad and a painful way at that point. You have a higher chance of dying from a sickness with CTE.
comment below if you have questions or DM me and we can continue this.