The fact that he is saying "can't" in this situation is pretty disingenuous. The probability of a planet of it's size forming around a star that small are just very small but not impossible.

This wouldn't even be something entirely new if you throw in all star types into the mix. We have discovered planets orbiting neutron stars before that likely formed after the star collapsed into its neutron dense state.

But again, it's not refuting anything. The probability is still very small that saying "it wouldn't" form isn't necessarily a lie but we shouldn't always deal in absolutes when it comes to this stuff.