Shaykh Ahmad Bahā’ al-Dīn Ibn Yūsuf al-Hasanī was Shaykh Badr al-Dīn's younger brother

He accompanied the Naqshbandī authority in Damascus, Shaykh ‘Isā al-Kurdī, took the Tarīq from him, and was given Khilāfah in it. He later established his own Zāwiyah near the Umayyad Mosque

He uses to love and respect his brother Shaykh Badr al-Dīn, and would serve him in his private matters

He passed away over 20 years before his elder brother in 1329. At his Janāzah, Shaykh Badr al-Dīn brought forward Shaykh ‘Isā al-Kurdī to pray instead of him, knowing how much his brother loved his Shaykh

Although his father was a Qādirī and his brother a Naqshbandī, it's unknown which Tarīqah Shaykh Badr al-Dīn al-Hasanī was himself affiliated with

When people would approach him and ask for Tarīq, Shaykh Badr al-Dīn would tell them to follow the Sharī‘ah, adhere to the Sunnah of the Prophet ﷺ, and he would give them some Adhkār to read from the Sunnah

Muhammad Ibn Ja‘far al-Kittānī said about Badr al-Dīn al-Hasanī:

“There has been no match for him for 500 years”

al-Durar al-Bahiyyah (Pg. 93)

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Shaykh Mahmūd al-Rankūsī said: Once, Shaykh Badr al-Dīn's students were late to their lesson

When they arrived to Dār al-Hadīth, there was not a single person there except the Shaykh himself

And to their surprise, they saw that he had begun the lesson and was giving it without (apparently) there being any attendees!

On the 27th night of Ramadān, Shaykh Badr al-Dīn al-Hasanī would give his student, Shaykh Yahyā al-Maktabī, some Ottoman Liras, and would tell him:

“Go to the people of prostitution and tribulation, and give them this money. And tell the prostitutes to do Ghusl, repent, pray, ask for forgiveness, and to pray for Badr al-Dīn and all Muslims for forgiveness!”

Shaykh Yahyā says: “So I would do that, and I know that most of them truthfully repented, abandoned prostitution, got married, and became upright”

al-Muhaddith al-Akbar wa Imām al-‘Asr (Pg. 94)

Shaykh Mahmūd al-Rankūsī asked Shaykh Badr al-Dīn al-Hasanī about studying Nahw with a deviant teacher, since his deviance (supposedly) wouldn't affect such a subject

Shaykh Badr al-Dīn said: My son, if you sit in front of a mirror, do you not see yourself in it? It is the same with this, the teacher will undoubtedly reflect on his student

This was his routine and he would never abandon it. His time was preserved to the highest degree, such that you would never see him free to begin with”

al-Durar al-Bahiyyah, Pg. 82

Note: Shaykh Badr al-Dīn's house was connected to Dār al-Hadīth al-Ashrafiyyah, where he gave all his lessons, and that's how the students were still able to attend his lessons there