Aerys didn't trust anyone, not anymore, well, aside from his two Baratheon cousins, however, Steffon Baratheon was now dead. Aerys was certain that Steffon's death was an assassination, which is why he summoned you, the other Baratheon cousin of his, to his chambers.

Aerys' eyes were wild as he fidgeted upon the chair in his chamber, glancing around frantically to make sure nobody was hiding in his chambers before his gaze snapped towards his cousin and he spoke in a quick tone.

"Tywin is responsible...!"

Upon seeing the confusion upon his cousin's face, he leaned forward with a small hiss, clenching the arms of his chair tightly before speaking again.

"He is responsible for the death of your brother, of course!"