We've had these quarrels before. They lead nowhere but to an endless labyrinth of citations of documents till everybody's eyes glaze over. Stick to Drolesky's point. Why was Schillebeeck so prominent during the Council. The man was a heretic. He has had a huge influence. Deal with the big picture--the calamity that has befallen the Church--not with tiny bits and pieces of who said what when and why.
During the Council? Drolesky is quoting from his post-conciliar writings, it would seem. And even in 1968 he was able to defend himself before the Holy Office (then headed up by Card. Ottaviani) from charges of denying the Perpetual Virginity, which Drolesky charges with him here and seems to claim that he held (this denial) during the Council.