The thing is, since Chad returned, he has been sticking his nose into running the club. He has interfered with the help, accused one wrongly of theft, even refusing to give the guy's own money back to him. Sonny has been honest, always giving him, all this while, 50% share of the profits, even tho Chad did not spend a single minute working in the club, or for the club.
So Chad returns, immediately begins causing trouble, but o.k. he is a partner. So Sonny works on opening a 2nd club. Therefore, if Chad is going to be doing something which is bound to take up a great deal of his time, then he is obliged to let his partner know.