Fr. Chazal’s views are very interesting. His idea of the Pope “impounding” his authority because he is a heretic is reminiscent of Bishop Des Laurier’s thesis. Moreover both are Frenchmen and had a connection to the SSPX at some point. Lastly he grants that the post-conciliar Popes are indeed objectively heretics and perhaps even pertinacious heretics which is something that most Traditionalist Priests shy away from saying.
His book certainly is worth buying and his 2 hour lecture on the matter found on YouTube is also worth listening to.
I agree. I pointed out that his position very much resembles that of "sedeprivationism" ... against which Fr. reacted strongly, but I stand by it. He even uses the term "manifest" heretics. He says that they lack all authority but remain visibly head of the Church (formal vs. material in sedeprivationist parlance).
Basically, he's adopting the John of St. Thomas / Cajetan position regarding the disposition of heretical popes.