The phrase "instructing him on" is correct and usable in written English.
You can use it when referring to the act of teaching or providing guidance to someone about a specific topic or task.
Example: "She was instructing him on how to operate the new software."
Alternatives: "teaching him about" or "guiding him on".
Pinter had been due to give a reading of his poems, but throat cancer had impaired his voice and he asked Sands to step in, instructing him on how to deliver them.
Meanwhile, lawyers and police officers sent Mr. Guttman e-mail messages instructing him on the finer points of property law and advice on how to navigate the police bureaucracy.
DETROIT — A hostage standoff in Grand Rapids, Mich., ended late Thursday when a man suspected of shooting seven people to death, including his daughter and another child, earlier in the day killed himself as the police were instructing him on how to surrender, the police said.
Olivia and Mason remarry three times between them, sometimes disastrously, so that Mason Jr, who begins as a daydreamy five-year-old and grows into just the kind of arty, philosophical, mildly disaffected 18-year-old who wandered through Linklater's Gen-X-defining Slacker, has a succession of father figures instructing him on how to shape up.
Now Roland is making his own bid as Broadway's reigning nerd-hero, in the new musical "Be More Chill". He plays Jeremy, a high-school junior who is hopelessly devoid of social skills, until he takes a SQUIP—"super quantum unit intel processor"—a pill that implants a computer chip in his brain, instructing him on how to be cool.
At the White House Correspondents Association dinner on Saturday night, the Pentagon's Prince of Darkness lectured Hans Blix as if he were a colonial subject, instructing him on why an invasion of Iraq had been justified even though no weapons of mass destruction had yet been found.
Jack did not instruct him on the wardrobe or accessories; they were all his idea.
"We decided to take the wheel," Aldo said later, noting that his father had instructed him on what to do.
One day, the suspect drove the informer to a desolate stretch of desert and instructed him on using explosive devices.
It further instructed him on how to phrase his annual message on the Armenian Day of Remembrance: the President should refer to the atrocities as "genocide".
