Donald Trump's lawyers appear to be "handling" him so that he remains calm and does not overreact and try to fire Robert Mueller which would dramatically escalate the investigations.

Courtesy of Vanity Fair:  

With Donald Trump predisposed to self-sabotage in what may ultimately become an obstruction of justice case, the president’s lawyers have assured him that he has nothing to fear from Robert Mueller. It’s a tricky balancing act, given Trump’s past history of criticism for the special counsel. The president’s natural impulse for obstructive, combative behavior is also, in this case, a potential legal risk. So while F.B.I. investigators appear to have zeroed in on critical events that transpired before and after the real-estate mogul’s unexpected victory last fall, including Jeff Sessions’s recusal and the ouster of James Comey, Trump’s lawyers are taking pains to project calm, telling the president that he has nothing to fear and that the investigation, which some posit is just getting started, will wind down soon. 

“The people who have been interviewed generally feel they were treated fairly by the special counsel, and adequately prepared to assist them in understanding the relevant material,” White House lawyer Ty Cobb, who has urged the president to cooperate with Mueller and his team, told The Washington Post. “They came back feeling relieved that it was over, but nobody I know of was shaken or scared.” Cobb added that the idea that Mueller was looking beyond the election into Trump’s personal finances and business dealings—something Trump has said would be “out of bounds”—was incorrect. 

One of the goals of this effort, it appears, is to prevent Trump from flying into a rage and firing Mueller, as several of his allies have suggested he do if it appears Mueller is expanding the scope of his investigation into the president’s finances. “I’ve done my best, without overstepping, to share my view that the perception of the inquiry—that it involved a decade or more of financial transactions and other alleged issues that were mistakenly reported—just wasn’t true, and that the issues were narrower and wholly consistent with the mandate provided by the Justice Department to the Office of the Special Counsel,” he said, adding that he believes the investigation will be wrapped up by the end of the year, or shortly thereafter. As for further revelations regarding foreign contacts that are reportedly on the horizon, Cobb said he does not expect them to “unduly extend the inquiry.”

That last part is of course bullshit, and Trump's attorneys surely know that. 

So yes what they appear to be doing is trying to keep the orange shitgibbon calm so that the doesn't start throwing his feces all over the place and give the investigators even more to work.

Donald Trump is his own worst enemy, and clearly his lawyers know that he can only make things worse for himself.

I have to assume at this point that Mueller has every intention of issuing a subpoena for Trump's testimony some time in the near future, because that would really be the last nail in this coffin.