expression
he himself
Emphasizes that the action or state pertains to the man himself, not someone else. Used as a noun-like expression.
彼個人がその決定を下した。
He himself made that decision.
noun which may take the genitive case particle 'no'
his personal
Used attributively with の to mean 'his own' or 'personal to him', as in 彼個人の意見 (his personal opinion).
これは彼個人の意見であって、会社の見解ではありません。
This is his personal opinion, not the company's view.