On Virginity (Coptic fragments) — as quoted by Pitre (p 113); translation: Coptic text edited by L. Th. Lefort; English
If she had had other children, the Savior would not have ignored them and entrusted his Mother to someone else (John 19:26–27); nor would she have become someone else's mother.
No freely usable English translation of this passage is online, so the note keeps Pitre's quotation and links to the full text. Translation: Coptic text edited by L. Th. Lefort; English as quoted by Pitre.
Why Pitre cites it
'If she had had other children, the Savior would not have ignored them and entrusted his Mother to someone else.' Athanasius reads John 19:26–27 exactly as Pitre does.