I think his office had been blowing up his phone with calls trying to locate SS and he didn't answer so the office contacted his sister. He pretty much had to answer his sister or she probably would have asked police to make a welfare check.
JMO
There's never been any indication that his office thought he was missing. Remember, he's often at the dojo, he has several businesses, he doesn't stay in one place. There has been absolutely no indication of concern. frankly, they would go to the house before they would call an out of state sister -- what would she know? I think she got the day wrong.