@olcharlieboi In a lot of cases amnesia doesn't wipe the entirety of your memory. Only episodic memory stores specific personal experiences in a person's life, which is what Aaron lost. Semantic memory, however, is what stores factual information, which, fortunately for him, remained largely unaffected. Additionally there's an entire separate category of memory known as procedural memory, which is sort of the subconsciously stored knowledge of things you've learned throughout your life.
For example, as the years by, you may not remember the exact events of how you learned to ride a bicycle, but when you actually get on a bike, you still know how to ride it. The accident occurred when he was fourteen, so his literacy and all his motor skills are still well intact.
With that said, while I obviously can't make any surefire predictions on how the roleplay will go, I believe I can write Aaron as a functional enough person that his condition will be relatively self-contained, and won't have much effect on the environment and overall plot of the story taking place. I mean, it would pretty much have to be, since he's trying to keep it a secret for as long as he can.
The only things its designed to affect are his motivations and the way he builds up relationships with the other characters. If it's still a no-go, though, I understand.