Executive privilege does not apply:
In a sealed decision that could clear the way for other top Trump White House officials to answer questions before a grand jury, Chief U.S. District Judge Beryl A. Howell ruled that former Pence chief of staff Marc Short probably possessed information important to the Justice Department’s criminal investigation of the Jan. 6, 2021, attack on the Capitol that was not available from other sources, one of those people said.
Trump appealed, but the U.S. Court of Appeals for the District of Columbia Circuit refused to postpone Short’s appearance while the litigation continues, the people said, signaling that attempts by Trump to invoke executive privilege to preserve the confidentiality of presidential decision-making were not likely to prevail.
I've noticed several friends asking, "What is Merrick Garland waiting for?" He's not waiting. Hasn't been waiting. A true bill of indictment handed down by a Grand Jury is the proper approach in any controversial prosecution, and this one is without a doubt the most controversial one. No former/current President has ever been prosecuted for a crime, so we're in unexplored territory here. Of course this is taking a long time, because Trump is fighting every move the DOJ makes: