This seems like a fucking Hail Mary where they know they are fucked.
Lying to Mueller is a crime. It seems the height of a dangerous plan to put a client who has already been caught committing perjury in the past, is known for lying publically and flagrantly, and can barely read a 5 minute speech off of a piece of paper without making a false statement to Offer an interview with Mueller.
I suspect this means that they know they cant avoid it, so they have to do it now.