I found these two statements on Natan Slifkin’s website:
According to this, it was Rav Chaim Kanievsky Shlita and not R’ Elyashiv Zatsal who MIGHT have made the statement about geirim. We do not even know for sure that R’Chaim said that. Also, the way it is phrased, it is not referring to someone who already converted and we are not saying his geirus is possul; rather it is saying that we should not convert him to begin with (but it might be possible that his geirus is accepted after the fact).
In terms of the other statement, he only says that R’ Elyashiv is reported as saying it.
These statements were made in an article in which Natan Slifkin was trying to show that the Gedolim do not believe the world is older than 6 thousand years, and yet, he didn’t have proof that R’ Elyashiv Zatsal & R’ Chaim Ybdl”c actually made those statements.
I’m not saying that they definitely didn’t; I am just saying that no one has brought proof yet that they did. And if Natan Slifkin who had an agenda to show that the Gedolim are against the belief that the world is more than 6 thousands years old couldn’t bring any proof that they actually said that, it makes me wonder if they in fact did. If anyone has any proofs/sources on that matter, please provide. Thanks!