Al-Khateeb Al-Baghdādi (rahimahullāh) said in Sharaf Ashāb Al-Hadeeth (no. 41):
“There is not one from Ahlul-Hadeeth who would show favouritism – when narrating hadeeth – to his father, nor to his brother, nor to his son. We have, as an example, ‘Ali Ibn Abdillāh Al-Madeenī, who was an Imām of Hadeeth in his era. Not a single word is reported from him that he ever strengthened [the narrations of] his father – rather, the opposite of that is narrated from him.”
Abu Khadeejah Abdul-Wahid