I don't think obviously legal. I think you're right about the standing issue, but ignoring that, if it had reached the merits without any problem with standing,

I don't think obviously legal. I think you're right about the standing issue, but ignoring that, if it had reached the merits without any problem with standing, I think it is not obvious that the policy fits within the bounds of the HEROES Act. I really dislike the major questions doctrine - because I think it should be up to Congress to write laws without some other body second-guessing them about which parts of those laws are or aren't "major" - but I'm also not a strict textualist and often don't find these pure text-based arguments very compelling.