Probation.
I don’t know Florida law, but most states forbid you to shoot the bad guy once he turns away and retreats.
Whether that is reasonable or not is not the case. It is the law. You are supposed to call the cops and let them pursue the bad guy.
His best hope would be jury nullification, but that happens relatively rarely.
Regardless, anyone who owns a weapon is a fool if he does not know the law and how the local prosecutors interpret the law. There are too many traps for the unwary.