That's what I thought, you've never read the books and are relying on a handbook type entry. IIRC it's been stated multiple times that the reason he was frail was that he was a sickly kid due to environment and genetics.
However, even the entry your trying to use states that he made it through a "rigorous physical and combat training and selection process" before being selected, which goes against your claim that he had no will or determination.