I don't think you understand the speed of light.
Because of time dilation being a thing, he's not 100% incorrect. There's also no way to prove him right or wrong, simply because reaching the speed of light with a physical object is impossible. (According to our current theories)
If you somehow manage to break the laws of the universe and travel at the speed of light, then assuming time dilation is indeed true (it's been proven in the past as being a thing), and also assuming that the theory of relativity is fundamentally correct then yes,
from your perspective, you would be there instantly.
It's worth noting that for any observers it would indeed take thousands of years for them to get there, but saying that it's not possible within a human lifespan would be inaccurate assuming you're able to move at the speed of light.
The universe itself does not allow anything to match (let alone exceed) the speed of light unless it has literally 0 mass. Even if somehow we could reduce a spacecraft and human passengers to 0 mass, then there would be no possible way to build up the energy required to reach the speed of light. Photons are different; they essentially
are energy, and have 0 mass. They can easily reach the speed of light, but never faster.
