When Bishop de Saint-Vallier became ill in September 1715 and was left with a fever which could not be cured, he sought spiritual help at the tomb of Brother Didace in Trois-Rivieres.
Bishop de Saint-Vallier witnessed to his cure in these words:"It was not until the last day of the novena (nine days of prayer) I was making in church where his body lay entombed that I felt better and was cured. It was the will of God, obviously, that everyone in my diocese realize how much He valued His Servant (Brother Didace), for in making me aware that my illness worsened, even during my novena, I had to acknowledge that my cure was due only to the perseverance with which I asked His help through His servant. I am a witness to this truth, and I speak of it willingly to show my gratitude and to encourage you to place your confidence in this holy Recollet brother, whose virtues we should all imitate."
Brother Didice has been nominated for beatification and there is a movement to have him canonized.