You grab your brother by the shirt and yank him out of the chair with all of your strength. You hear fabric tear as you pull him up to a standing position and stare into his eyes. You say his name a few times.
He regains focus quickly. "Dear God," he says, "how long was I in that thing? How long did you let me sit in that thing?"
"Less than five seconds," you say. "I pulled you out as soon as you seized up."
You can see that he doesn't believe you at first. Then he gets a faraway look in his eyes. He doesn't speak again for some time.
If You are no longer interested in the chair after seeing your brother's reaction that's one thing, but otherwise it is time that You sit in the chair after your brother.