I was glad to read this towards the end of his dissertation, and there is certainly a salutary message here for the SSPX:
"Can we therefore be morally certain that the tenant of Santa Marta is a false prophet? My answer is: Yes. Are we therefore authorized in conscience to revoke our obedience to one who, presenting himself as Pope, actually acts like the biblical boar in the Lord's Vineyard, or like the hireling, qui non est pastor, cujus non sunt oves propriæ (Jn. 10:12), et non pertinet ad eum de ovibus (ibid., 13)? Yes.
"What we cannot do because we do not have the authority, is to officially declare that Jorge Mario Bergoglio is not Pope. The terrible impasse in which we find ourselves makes any human solution impossible.
"Our task must not be to grapple with abstract canonical speculations, but to resist with all our strength - and with the help of God's Grace - the explicitly destructive action of the Argentine Jesuit, rejecting with courage and determination any collaboration even indirectly with him and his accomplices."
However, it disappoints me that he appears to be saying "he's not the pope, we just don't have the authority to say it". He has never once called him 'Pope', so he is effectively declaring it anyway: 'Jorge Bergoglio', 'the tenant of St Martha'. But if we are not allowed to declare it, there is a reason: there needs to be a conviction of heresy (by a Council according to St Robert) before the declaration, formal heresy needs to be established. Whatever we might think the outcome of such a process may be, we may not presume, because, as Archbishop Lefebvre said, nothing is impossible with God. If we cannot declare he is Pope, then he is to be held as Pope and addressed with the respect due to that exalted office, however unworthy an occupant he may be.
He gives a whole stack of reasons why Pope Francis is not truly pope before saying this - the possibility that Benedict's resignation was not valid, lack of consent, involvement with the deep state and intention to destroy the Church. I do not see how all of this can be regarded as anything more than conjecture, not Catholic dogma on the papacy.