Is the phrase "My poor father, I told him: 'Tomorrow is the first of Dhul-Hijjah'"—intended solely to express sadness for him—considered backbiting?

It appears that what was mentioned is not backbiting, but rather an act of compassion. The forbidden backbiting is when you mention your brother with something he dislikes, as stated in the Hadith: "Backbiting is your mentioning your brother with something he dislikes." It was said, "What if what I say is true about my brother?" He replied, "If what you say is true about him, then you have backbitten him; but if it is not true, then you have slandered him."