Some people from NJ do say they are from NY (since the state and the city have the same name, it just depends what you mean).
Plus, he could have moved from one suburb/state to another suburb/state all while being in the same metro area. So for all we know he could be 'from Missouri' even if he currently resides in Illinois. Or Alaska for that matter.
More importantly, the absolute geographic lines are less important than the idea/intent. Someone from Lapeer might describe themselves as being "from Detroit". If your audience isn't familiar with Michigan, it gets the job done.