Now appellate practitioners will never know how it turns out. See White Collar Crime Prof Blog, who writes:
Unlike the criminal case, civil claims against Lay, such as the SEC's case and the securities class action, will continue against his estate. However, because the criminal conviction is wiped out, the plaintiffs cannot rely on it as proof in their case, if my dim memory of collateral estoppel serves me right.
See United States v. Estate of Parsons , 367 F.3d 409 (5th Cir. 2004) ("the appeal does not just disappear, and the case is not merely dismissed. Instead, everything associated with the case is extinguished, leaving the defendant as if he had never been indicted or convicted.").