Peace be upon you. The historical sources from both Sunni and Shia traditions indicate that when Imam Hussain wanted to bury his brother Imam Hasan next to their grandfather, the Prophet Muhammad, a group of people prevented him from doing so. There is much discussion among scholars regarding this matter. For those seeking more information, I recommend referring to the books 'Al-Kafi' and 'Bihar al-Anwar' from our sources, as well as 'Sahih al-Bukhari' from other sources. Praise be to Allah, the Lord of the worlds, and blessings and peace be upon our master Muhammad and his pure family.