I understand that. My point was that if he can keep up with the literal WC in blitz, it's extremely likely that the strength displayed by him in the Sinquefield

I understand that. My point was that if he can keep up with the literal WC in blitz, it's extremely likely that the strength displayed by him in the Sinquefield cup was in fact genuine. People aren't usually hundreds of ELO points stronger in blitz than in classical. At least not at the GM level. Again, actually looking at his games from this tournament leaves no reason to suspect cheating.