It's complicated.
First of all, a lot of the Saikou family stuff is heavily plot-related, so to say too much would ruin the game.
That being said, there are some things we know for certain.
1. Kencho is Megami's little brother, so if she dies/disappears/whatever, he'll become heir to Saikou Corp.
2. According to the official website, he doesn't appear until Week 52.
3. Kencho is in junior high, (aka middle school), which is why he won't attend Akademi until much later.
4. Because he was created as a back-up in case anything happens to Megami, he hates feeling inferior and would be happy if something bad happened to her.
I hope that answered some of your questions. Oh, and if you still wanna volunteer, visit the official website.