Tell him what reality is---that you will still be you no matter where you are. A change of scenery, or a geographical solution as it's called when someone thinks going someplace else will magically fix everything.

Maybe you could meet somewhere in the middle on this: agree to take advantage ot the opportunity and at the same time realize that it is just an educational opportunity and not a solution. I agree that reality, as compared to his magical thinking, might be a jolt when it happens.

I wish you the best in your endeavors!