Attorney "lost" husbands client file????

I assume that you were acting on behalf of your husband, who was the attorney's client to whom he owed a duty.  I also assume that all amounts owing to the attonrey have been paid; if not, the attorney (at least in New York, and I doubt Texas is different) the attorney would have a retaining lien on the file and wouldn't be required to release it. You have every right to be angry at an attorney who lost the file, and perhaps to sue for malpractice (a very tough case, I am not recommending it) and/or file a grievance with the disciplinary committee, but that won't help you pursue your appeal.  However, you should be able to get whatever documents you need from the Court's file, which you should be able to obtain from the clerk of the court - an appeal has to be based on the record before the lower court, so anything that was not in the Court's file would probably not help you.