They can, through his lawyer, in writing. They can get their answers the same way.
Republicans should really stop defending trump now. Once he’s removed there is still hope the party might recover in a few cycles. The further his exposure goes, the worse it will be for everyone in the splash zone.
Instead it looks like republicans will stand by their monster till they crumble under pressure. A sad end to and initially noble party that had good moments until as recently as 60 years ago.