Yeah it's a very very short proof that uses no mathematics developed within the last 30 years. Which doesn't necessarily make it wrong, but in the absence of mechanization in Lean or proper peer review I think this it is premature to post this. Notably the unit distance proof did not fall into this category.

I would assume/hope they had someone verify it before publishing

I'd guess that verdict (or its opposite) is to come within the next 24 hours.