I have often wondered whether he believed Benedict was pope when reading his writings. More often than not, he would refer to Benedict as Benedict, but Francis as Bergoglio. That is why I wonder what he will say.
He did muse at one point that it was possible that Benedict was still the pope, and that it should be investigated. If I recall, he was more focused on the St. Gallen mafia situation than the resignation, which would disqualify Bergoglio but not make Ratzinger pope.
I do think +Vigano has a special animosity against Bergoglio, but I don't believe he's the type that would let those emotions dictate his theological position, as seems to be the case with most Bennyvacantists.
As I said, he's consistently traced the rot back to Vatican II and the NOM, and even if he concludes that Ratzinger was pope until he died, this wouldn't be for him a "solution" to the larger crisis.