We have both Fr. Khoat's words and actions in 1988 and 1989, which deny that Siri was ever Pope or ever had any claim to the papacy!
On October 17 to 24 David Bawden went to Port Arthur, Texas to visit with Fr. Khoat concerning the Siri claim. Now, if Siri were Pope Gregory XVII, Fr. Khoat would have sought faculties from him to function in these extraordinary times. Rather he states that a priest who was trying to find out who the Pope was and defend the Faith has faculties in these times from the Church, since the lawful authorities cannot be approached. Now remember Fr. Khoat saw Siri in June of 1988.
On the Friday before Palm Sunday, March 17, 1989, Fr. Khoat celebrated the Mass of the Ferial Day, rather that the Mass of the Feast of Our Lady of Sorrows. (He also omitted Saint Patrick, which is curious.) This proves that Khoat accepted the changes in the calendar by Pope John XXIII in 1960 as laid out in the Modernist inspired decree Rubricarum Instructum. If Siri was elected in 1958, then these revisions were promulgated by an antipope, and therefore invalid.
A week later on Good Friday, Khoat added to Jesus' sufferings by stating: I like the position of Archbishop Lefebvre in regard to the Pope. Now Lefebvre's position has always been that all of the usurpers in Rome from John XXIII to John Paul II were valid Popes, which therefore proves that Siri was not Pope.
Fr. Khoat gave a retreat from Easter Sunday to Low Saturday. On Thursday, March 30th, Khoat repeated his statement in regard to Lefebvre's position in the presence of three witnesses. Gary Giuffre was immediately informed of this and came over to prove that John Paul II and his predecessors were antipopes the next evening. Khoat silently watched Giuffre's presentation, which also stated that Siri had been elected in 1963 and both 1978 elections. If Khoat new that Siri was actually elected and accepted in 1958, why did he not correct Giuffre at this time. No, we must accept that Khoat's silence confirms that he had no idea Siri had ever been elected. Remember Giuffre paid $15,000 to send Khoat to see Siri for the sole purpose of finding out if the proposition were true or not and to attempt to have Siri recognized as Pope and taken away from his alleged captors, if any. Khoat as Giuffre's agent was obliged morally to give Giuffre a COMPLETE REPORT. It appears that he gave Giuffre no report, until it was convenient to do so for his own ends.
The first public claim that Siri was elected and accepted in 1958 was made on Pentecost, June 3, 1990. A month before Khoat received a copy of Will the Catholic Church Survive the Twentieth Century? which proves that Siri could not have been Pope, countering the claim that Siri had been elected in 1963 and both 1978 elections. This book also for the first time definitively proved that the 1963 election could not be valid. Therefore, we must presume Khoat's change of story resulted from this proof rather than from his June 1988 meeting with Siri.