As early as 1919, Msgr. Bruchési had felt the symptoms of a strange evil characterized by a mixture of physical depression and moral anguish that deprived him of all initiative and decision-making capacity. It was observed that his illness coincided with the death of a vicar general whom he loved very much, Msgr. Émile Roy. Some saw it as the consequence of the strong pressures to which the archbishop was subjected during the war and which would wear him out prematurely.

Thus, for eighteen years, Msgr. Bruchési lived in the shadow of the cross, fulfilling more than ever his motto: In God I entrust myself. On October 18, 1921, Msgr. Georges Gauthier, his auxiliary since 1912, was appointed Apostolic Administrator, and on January 24, 1923 he became coadjutor with the right of preferment.

Subsequently came fifteen years of a sort of imprisonment in the archdiocese's apartments, followed with the last three years which allowed him to go out a few times to visit religious communities. Msgr. Gauthier remained compassionate and always surrounded him with deep veneration.

On September 20, 1939, Msgr. Paul Bruchési rendered his soul back to God. He was 84 years old. His funeral was celebrated at the Cathedral in front of a considerable audience; a gathering of about thirty bishops, hundreds of priests, and a crowd of faithful. They were presided over by Msgr. Georges Gauthier, who concluded his predecessor's eulogy with these very appropriate and touching words:

“We have the firm hope that you have entered into the definitive rejuvenation of Heaven. Live gloriously in God's bosom. We will follow you there from our filial and faithful memory, making the words of Saint Paul our own: ‘Remember your leaders who spoke the word of God to you. Consider the outcome of their way of life and imitate their faith.’ (Heb 13:7)”