light novel kamijou touma memories

Hi mates i watched the anime all seasons i wanted to read the novel but my friend gave me a spoiler that at the end of the light novel he dont remember anything about misaka mikoto ,index , his right hand and other characters. I want to know if this is true .If it is true then in my opinion is stupid .Beacuse he have his adventures and at the end hi lost his all memories. Please tell me if this spoiler is true if it then what is the sense of him losing memories. Sorry if i made any errors in writing im not from england or america

light novel kamijou touma memories