>>22181707 (lb) DoD directive regarding release of information when House member or Senator is injured, dead or missing (missing means not at the post they are supposed to be at) while being transported by military or on a military installation.
Notice that all of those in the line of succession will not have information released by military. Only the WH can respond to their whereabouts
https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodi/541001p.pdf?ver=uiQx4xnd0u2nQZLEYI_4DA%3d%3d