«وَلَا ذُو خِلَالٍ حَازَ مِثْلَ خِلَالِهِ»
No person of fine traits possessed qualities quite like his.
Nidd means peer or equal; khilāl refers to traits or qualities. In the verse, the beloved companion becomes incomparable in the speaker’s esteem.
This is the language of affectionate poetic intensification. Admiring someone as unmatched does not independently verify every aspect of their conduct or every claim they make.