Faolan gives her a good scratch while she steps forward towards Sirius, hoping that it will encourage her to feel more comfortable about the scenario of a strange man in her house and Lancelot still nowhere to be seen. "That's it, good girl," he reassures her, ruffling her fur as he does. "This is Sirius, he's going to help us find Lancelot."

He's not certain he really needs to be explaining this to her. He's not sure that she will really understand what he's saying but he feels compelled for some reason to explain regardless. Perhaps because he knows that's what Lancelot would be doing.