The phrase "as he frequently does" is correct and usable in written English.
It can be used to indicate that someone regularly performs a specific action or behavior.
Example: "He arrived late to the meeting, as he frequently does."
Alternatives: "as is often the case" or "as he often does".
As he frequently does, Mr. de Blasio offered an implicit rebuke of the Bloomberg administration.
He had left his wife and young son in England, as he frequently does, and was relieved to have company.
As he frequently does when he says something unwise, Turner apologized, blithely assuming that the furor would pass.
A week after the Dirty Dog Derby, Mel's father, Ron Behm, stopped by her place from his home next door, as he frequently does.
Broad-shouldered and barrel-chested, Mr. Reynolds is physically imposing, especially when he leans in to speak to someone in person, as he frequently does.
At that very moment, Mayle revealed, he was carrying his Springfield Xd.45 handgun, concealed in a tuckable hip holster, as he frequently does off campus.
Family madness provided an excuse when Bowie felt the need to explain himself, as he frequently did.
She tried to see her brother when he came to the East Coast, as he frequently did, to teach, but usually he didn't call.
As he frequently did, he invited any and all neighbors to visit the company and see what goes on there for themselves.
She took three days off and was back at the office the Tuesday after her wedding.Two days after Mr. Obama's election, Mr. Emanuel called a reporter friend, as he frequently did.
Whispering into my left ear is the late Lindsay Anderson, asking, as he frequently did as a moral test: 'You don't take the Oscars seriously, do you?' The Oscars have been awarded since 1927 by the Academy of Motion Picture Arts and Sciences, the nominations made by the 13 arts and crafts divisions and the full 5,000 members all voting to produce the final results.
