Agreed with DPG and Foxtrot25.
Even true stories need to be adapted for the screen, in other words, you'll need to take liberties with the 'facts' and change them to best fit a script.
Is there one thing that he did that stood out from the rest? Or one thing he did that he is best known for? If not, is there something you can make up as a seminal achievement?
On a side note, dyslexia is NOT a flaw. Most dyslexia is a result of a different brain structure to the norm, it's not something the main character can overcome or control but learn to work within his or her life. I should know as I was diagnosed with Dyslexia and have been struggling with it for years, yet at the same time, my brain's unique information processing has given me some advantages.