"initiated him" is a correct and usable phrase in written English.
Generally, it is used when someone starts something, especially something involving another person. For example, "John initiated him into the secret society."
His brother, who lived in Brentwood, belonged to MS-13 and initiated him into the gang.
When Lambert was a schoolboy of 11, a teacher initiated him, and he "felt no shame or fear, only gratitude".
Amid his early struggles to sell records, he was fortunate, in 1990, to come under the tutelage of T Bone Burnett, who initiated him into the production game.
He got a weekend job working for a bullion dealer, in Pennsauken, New Jersey, who initiated him into the idiosyncrasies of the trade in coins and gold.
His early professors initiated him into the rigors of fieldwork during summers on the Colorado Plateau and in the Montana Badlands.
She gives us sharp Dickensian portraits of her father's two closest friends -- the kindly Salvatore, whom he will cruelly betray, and the flamboyant, unsavory Joe Morton, who first initiated him into a life of crime.
Instead, he is intercepted by another uncle, a disreputable blues-lover and philanderer, who initiates him into blues culture.
Mark Lowe replaces Gonzalez for the top of the eighth, and Yadier Molina initiates him with an R.B.I. double.
By Tuesday, the Arizona Cardinals were getting ready to initiate him by sending as many players as possible straight at him when he drops back to punt.
If you're Anne of Austria, mother of Louis XIV, you hire a one-eyed 40-ish noblewoman named Catherine de Beauvais to initiate him into, ahem, adulthood.
Nowadays, when a star signing is introduced to the White Hart Lane crowd, the fans initiate him with a rapturous chant of "Yiddo!
