Mother Geneviève died in 1891. Here are some elements to establish what she could think of Thérèse:
Mother Geneviève de Sainte‑Thérèse was 82 years old when young Thérèse entered. She was in favor of this entry and opposed the Superior of the Carmel on this subject. She had enough confidence in Thérèse to entrust her with intimate memories, which the young Carmelite transcribed - read here.
Moreover, Thérèse herself mentions the foundress three times in the writing of her Manuscript A.
She first evokes him just after his death, on folio 12 verso:
The day or the day after Mom left, he took me in his arms and said to me: "Come and kiss your poor little Mother one last time." And I, without saying a word, put my lips to my darling Mother's forehead... I don't remember having cried much, I didn't tell anyone about the deep feelings I felt... I looked and I I listened in silence... no one had time to take care of me so I saw many things that people would have liked to hide from me; once, I found myself in front of the lid of the coffin... I stopped for a long time to consider it, I had never seen one, however I understood... I was so small that despite the low height of Mom, I had to raise my head to see the top and it seemed very big... very sad... Fifteen years later, I found myself in front of another coffin, that of Mother Geneviève, it was from same size as Mama's and I still thought I was in the days of my childhood! no longer had to look up to see him; she no longer lifted it except to contemplate the Sky which seemed very joyful to her, because all her trials had ended and the winter of her soul had passed forever...
Further on, Thérèse recounts her entry into Carmel and speaks of the presence of Mother Geneviève in the choir when she entered (folio 69 verso):
Like all the postulants, I was taken to the choir immediately after my entry; it was dark because of the exposed Blessed Sacrament and what first struck my eyes were the eyes of our holy mother Geneviève who fixed themselves on me; I remained on my knees for a moment at his feet, thanking God for the grace He granted me to know a saint.
Finally, Thérèse in folio 78 and 79, shares her heritage with us:
The following Sunday, I wanted to know what revelation Mother Geneviève had had; she assured me that she had not received any, so my admiration was even greater, seeing to what an eminent degree Jesus lived in her and made her act and speak. Ah! this holiness seems to me the truest, the holiest and it is she that I desire because there is no illusion there... I do not attach importance to my dreams, moreover I I rarely have any symbolic ones and I even wonder how it is that, thinking all day long about the Good Lord, I don't pay more attention to it during my sleep... ordinarily I dream of the woods, the flowers, the streams and the sea and almost always, I see pretty little children, I catch butterflies and birds like I've never seen. You see, my Mother, that if my dreams have a poetic appearance, they are far from being mystical... One night after the death of Mother Geneviève I had a more consoling one: I dreamed that she was making her will, giving each sister something that had belonged to her; when my turn came, I thought I would receive nothing, for she had nothing left, but rising up she said to me three times with a penetrating accent: "To you, I leave my heart."