Being asked by lawyers to instal spyware on personal devices - is this… okay?

Long story short, there is an ongoing legal case (not criminal), and the defendant is being requested by lawyers of the opposing team to install software that will search through all personal devices for certain keywords in messengers, emails, browser history and etc. All of that is planned to be reviewed by the legal team and considered for suspicion.

Does anyone know, is this a common practice? How is it being used? What kind of spyware is that? What would …

devices lawyers personal personal devices privacy spyware