He is already making his pitch: I read x books but you only need x-6 books to succeed. Sign up today, space is limited.
Here is another promotional post from two months ago:
1) If he's not hired, how is he going to sell his service? People will say "He couldn't even get himself hired!"
2) If he is hired and does a side job of teaching others for Google Interview, that's a gigantic conflict of interest (and probably a breach of NDA). He will be fired.
Is he planning to get hired, quit on the spot, and then start his tutoring service? (Well, stranger things have happened...)
Of course, things get muddier since Google does almost everything. But I doubt they'd want to engender ill will by suing an ex-employee for ownership.