The 9/11 fires were many times hotter than the Grenfell Tower blaze. The World Trade Towers were soaked with jet fuel, and burned hot enough to melt and warp steel, and disintegrate concrete. The Grenfell fire was mostly wood, paper, synthetic materials, and plastics which spread fast from one apartment to another but not as hot. It is like comparing a blast furnace to a BBQ,  The Grenfell Tower is now extremely unstable and may very well collapse under its own weight.