Not at all. If this Pope declares homosexuality is no longer a sin he de facto ceases to be Pope.
St. Thomas Aquinas:
“In the case in which the pope would become a heretic, he would find himself, by that fact alone and without any other sentence, separated from the Church. A head separated from a body cannot, as long as it remains separated, be head of the same body from which it was cut off.
“A pope who would be separated from the Church by heresy, therefore, would by that very fact itself cease to be head of the Church. He could not be a heretic and remain pope, because, since he is outside of the Church, he cannot possess the keys of the Church.”
St. Robert Bellarmine:
*”...a pope who is a manifest heretic by that fact ceases to be pope and head, just as he by that fact ceases to be a Christian and a member of the body of the Church; wherefore he can be judged and punished by the Church. This is the judgement of all the early fathers, who teach that manifest heretics immediately lose all jurisdiction.”
Ah, but it looks as though the Pope won’t be doing it...his “synod” will be doing so.
But who gets to make that call? The ecclesiastical theology of the Catholic church as it currently is (post 1870) makes that VERY hard to do.
Now, I have asked this a few times and you are the first with some quotes (thank you for that!). But is there anything in canon law relating to an apostate or heretical Pope?
Jesus should be the head of the church
This is actually believed to have happened once when Pope Sixtus V - thinking himself a great Latin scholar - decided to retranslate the Vulgate with disastrous results.
Pope Sixtus V, 1585 - 1590 was, in most repects, a very successful pope. He eliminated lawlessnes in northern Italy, re-filled the Vatican treasury by the use of good business sense and gained control of a rambunctious college of cardinals. What he was not was a Latin scholar. Nevertheless, he re-translated the Vulgate. The result was a Bible of errors.
He had already issued the bull on his new Vulgate and had it printed. The night before it was to be issued, he died, apparently of natural causes. St. Robert Bellarmine re-re-translated the Vulgate, correctly, and it was issued properly.
http://www.newadvent.org/cathen/14033a.htm
This is a great example which can be used to illustrate the protection the Holy Spirit exerts over the Church and the pope, to protect them from error in faith and morals. Before he was about to promote it "ex cathedra," he suddenly died.