He states that he was personally acquainted with Shoghi Effendi and was aware of the weaknesses of ‘Abdu’l-Bahá’s family members,. He specifically recounts an incident involving Shoghi Effendi and Dr. Zia Baghdadi. Sobhi describes a time when they were together making jokes typical of young men. He claims that after briefly leaving the room and returning, he witnessed them drinking wine. When Sobhi questioned Dr. Baghdadi about what they were doing, he reports that Shoghi Effendi turned to him and said, "If you want some too, come and drink".
(The Memoirs of Fadlullah Mohtadi Sobhi)
https://archive.org/details/payam-i-pedar-sobhi/payam%20i%20pedar%20sobhi/
For instance, I frequently encountered Haj Mirza Haydar-Ali, their great ninety-year-old missionary, and the sons-in-law of Abbas Effendi in a state of intoxication at the Haifa gathering. I used to wonder if perhaps they were drinking as a sin, contrary to the will of Abdul-Baha.
That was until I fell ill in the Haifa guest house. When my weakness was reported to Varaqiyyi-ulya (the daughter of Baha'u'llah), she sent me a bottle of 'medicine' with a message saying: 'This medicine is strengthening and beneficial; it is exactly the same medicine that His Holiness Abdul-Baha used to partake of.' When I opened it, I saw it was wine. I did not know whether the Lady considered me so foolish and uninformed, or if she sent it knowingly.
At that moment, I understood the intoxication of the sons-in-law, and I also confirmed the statement of Zill-os-Soltan, who had said: 'One night in Paris, I shared a cup (drank) with Abbas Effendi.'"
(Abdul Husayn Ayati 'Avarih', Kashf al-Ḥiyal, Vol. 1)https://archive.org/details/kashful-heel-part-3/Kashful%20Heel%20-%20Part%201/