I thought you first wrote about putting the defendant at risk of cross-examination in a criminal case because of the civil testimony. Now it appears you are writing as to if the sworn testimony in the civil case can be used in the criminal.As plaintiff in the civil case he can't hide behind self-incrimination. But, he would still be able to hide against self-incrimination if the criminal case were to reopen, and the prosecutor sought to use testimony in civil case as evidence?
You've got to maintain a coherent narrative to have any chance of help.