I didn't want to draw an early conclusion before both Dream and the Mods who removed his speedrun had given their statements and it's fair to say Dream cheated. The likelyhood of him actually pulling this off is way too small, to a point where simulations can't recreate it.
I suggest checking out Karl Jobst's Video on the topic, he has a nonbiased view on the situation and explains his conclusion very well, citing all the evidence along the way.