It is rather public knowledge that presidents take home documents, even disputed ones. Obama took 30M documents home, Nixon, Carter and Reagan released the last of his documents in the late 2010s, JFK family is still holding on to a ton of documents about the Bay of Pigs debacle and subsequent Cuban missile crisis, some of those documents won’t be released by the JFK library for another 50 years or so presumably because they would be damaging to the image of the late President.
Presidents have broad power over classification, since they are in charge of the entire executive branch, they can simply verbally say they declassify something and that’s it. Typically there are some lawyers and the President’s library going back and forth negotiating over specific documents, at no point has anyone raided the Bush family or the Kennedy family.