Alright so it’s a colony NOT on the surface, hence the floating. Now the guy is still an idiot but the idea he’s pitching is hypothetically possible.

Oxygen is less dense than the Venusian atmosphere. So hypothetically speaking, one could fill a balloon with an O₂ and N₂ mixture that is slightly oxygen richer than here on Earth and the balloon would float above the vast majority of the Venusian atmosphere where all the acid rain and huge temperatures would be. Much like a Helium or Hydrogen balloon floats here on Earth because the gas is less dense than our atmosphere here.

So the idea is to make a balloon that is large enough to have people inside of it, because they can breath the lifting gas keeping the balloon afloat. The catch is, you aren’t above ALL of the atmosphere and there’s still a lot of caustic things that the balloon would have to account for, otherwise it’ll slowly leak. We don’t have a material that would withstand some of the things in the upper atmosphere of Venus. So the guy would literally have to invent a material that would be able to withstand the conditions or be self healing enough to deal with the conditions. Both are highly unlikely, not impossible but I sure as shit wouldn’t trust him on being the inventor of such.

So yes, the surface is inhospitable. But floating a colony above the clouds is doable and something that’s been investigated. At the 50km altitude of Venus, there’s still enough atmosphere to provide protection from harmful sunlight. The atmosphere at 50km is such that a balloon at 1.03 atm pressure would not have explosive decompression in the event of a rip, providing folks enough time to get emergency O₂ and ideally fix the tear. So basically, if a tear in the balloon did happen, it would be a light breeze and not a sudden POP as the oxygen escaped. So if the balloon is really, really big, it could take hours before the CO₂ slowly seeping in offset enough O₂ to start dropping your colony into the clouds of acid. And at 50km altitude, gravity there would be about 0.9g. Additionally, Venus is much closer to Earth than Mars, but since it’s closer to the sun, it’s actually a bit harder to get to.

So right around 50km above Venus is pretty much the most Earth like we’ve discovered in the Solar System so far. There’s just all this dizzying complexity to having a floating colony on Venus. And we don’t have anywhere near the materials or support infrastructure to really support anyone going to Venus, especially untrained people. But yeah you can see some of the renders NASA has done for a Venus colony. Here’s a page I found with one of the renders they’ve pitched.