Is speaking about an uncle who does not visit, and who cut ties with the speaker's father, considered backbiting, given that the speaker said to her son, "Pray for those who cut you off"?

If what is attributed to the paternal uncle—that he severed ties of kinship—would cause him distress if it reached him, then it is backbiting (gheebah) from which one must seek forgiveness and repentance, because backbiting is mentioning your Muslim brother with what he dislikes concerning any of his affairs. However, if there is no offense to him in that, then it is not backbiting.