the.com/handler

means Someone officially assigned to manage, guide, or keep control over a person, animal, or situation on another's behalf.

from From 'handle,' tracing back to Old English 'handlian' — to touch or feel with the hands, a close cousin of 'hand' itself. The word moved from physical touch to control in general over centuries: you could 'handle' a horse, a tool, a crisis. The '-er' suffix just names the person doing the handling. Its modern sense of 'minder of a public figure' is a natural extension — someone whose hands stay firmly on the reins, even if the leash is metaphorical.