Jared was the de facto re-election chair and not only did he not deal with election fraud in advance, he also actively worked to keep the admin from reforming Big Tech. Then he scrambled to keep the admin from effectively fighting the fraud after the fact. Now he’s likely—in his usual, underhanded way—going public as an election fraud denier while effectively trying to undermine the credibility of his FIL.
(Of course, I see Kushner as having been his FIL’s globalist/Deep State handler—talking with Rupert Murdoch daily?!?—all through Trump’s admin.)
It's not all on him. Trump claimed election fraud in 2016 and again in 2018 and did absolutely nothing to launch criminal investigations that would lead to charges and trials. If Kushner didn't deal with it then the same can be said of the President.