All because she had three Masses said for the repose of his soul
During the 17th century, a grieving young girl approached Benedictine Abbot Millán de Mirando at the monastery of Our Lady of Montserrat. She begged the abbot to say three Masses for her deceased father.
The young girl was totally convinced that these Masses would speed her father on his way to heaven, releasing him from the pains of purgatory. Moved by the girl’s child-like faith, the abbot said the first Mass the next day.
During the Mass, the young girl was kneeling and as she looked up she saw her father near the altar where the priest was saying the Mass.
She described her father as “kneeling, surrounded by frightening flames” and located at the bottom step of the altar. The priest was alerted to this miraculous phenomenon and he instructed the girl to place a piece of tissue where her father was kneeling. The tissue immediately started on fire for all to see, though the priest could not see the child’s father. This represented her father being purified by the flames of purgatory.
A second Mass was said for the repose of her father’s soul and again the little girl saw her father. This time he was up a step standing next to the deacon and was “dressed in a vibrantly coloured suit.” At this stage, her father was still in purgatory, but no longer touched by its flames.
At the third Mass, she saw her father for the last time. During the Eucharistic celebration he was “dressed in a snow-white suit,” but then something extraordinary happened at the conclusion of Mass. The little girl exclaimed, “There is my father going away and rising into the sky!” She no longer had to worry about the soul of her father as she knew with confidence that he had reached the gates of heaven.
Source: aleteia.org
