You ask someone if they can help you with a problem, and instead of giving you a simple yes or no answer this individual uses the opportunity to attack you and says if you hadn't done that, or if you had done that before, this would not happen to you.
One idiomatic phrase that may be relevant is Job's comforter. William Benét, The Reader's Encyclopedia, second edition (1965), has this entry for the phrase:
Job's comforter. One who intends to sympathize with you in your grief, but says that you brought it on yourself, thus in reality adding weight to your sorrow.
The reference is to a central element in the Old Testament's Book of Job. Three friends—Eliphaz, Bildad, and Zophar—come to see Job after multiple calamities have befallen him (through no fault of his own); and they argue, consecutively, "If thou wert pure and upright; surely now he [God] would awake for thee" (Bildad), and "God exacteth of thee less than thine iniquity deserveth" (Zophar), and "For thine iniquity teacheth thy mouth ... Thine own mouth condemneth thee" (Eliphaz). Job then responds, "I have heard many such things: Miserable comforters are ye all." (All quotations are drawn from the King James translation of the Bible,)
Speaking purely as an adult male American, speaking idiomatically, I would probably use "He is being an a**hole."