What did Julius Caesar see in Octavius to name him his political heir and heir to two-thirds of his estate?
While there is always more to be said, these answers touch on the subject:
What so impressed Julius Caesar about Octavian? by /u/PapiriusCursor
Is it possible that Caesar's will was forged by Octavian or one of his supporters? and Would Caesar's adoption of Octavian have been unexpected? by /u/XenophontheAthenian.