What is the ruling on reciting the Quran at the grave after burying the deceased?

Reciting the Quran after burial is both lawful and recommended. Al-Bayhaqi narrated in Al-Sunan Al-Kubra with an authentic chain of transmission — as stated by Imam an-Nawawi — that Ibn ʿUmar (may Allah be pleased with them both) recommended reciting the opening and closing verses of Surah al-Baqarah at the grave after burial.

Imam an-Nawawi noted in Al-Adhkar (p. 161), “It is recommended to sit by the grave for some time after burial, for about the time it takes to slaughter a camel and distribute its meat. During that time, those present should occupy themselves with reciting the Quran, praying for the deceased, offering exhortations, and recounting stories of the righteous.
Imam al-Shafiʿi and his students stated that it is recommended that they recite something from the Quran by the grave [of the deceased]; they added that it would be better if they were to complete the entire Quran.”

And Allah the Almighty knows best.