Responses
Amnesia can occur in many ways. It seems that he has lost his episodic memories which are involved in remembering life events specific to the individual. Whereas, in some cases people may retain their semantic (things like knowing the capital of France etc) and procedural memories (knowing how to ride a bike or tie your showlaces). So it seems his development hasn’t been hindered he knows everything an adult his age would but he has just lost the ability to recall his personal life events.
^shoelaces
It doesnt make sense to me and kinda irks me- if he is 30 something years old and has lost 30 years worth of memories. Wouldn’t he mentally be a child and behave as though he was younger?