Source: Shumara al-Sunnah, Jhelum
Answer:Yes, a non-Mahram man may also lower a woman's body into the grave.
It is reported that Sayyiduna Abu Talhah رضي الله عنه lowered Sayyidah Umm Kulthum رضي الله عنها, the daughter of the Noble Prophet ﷺ, into her grave.
[Ṣaḥīḥ al-Bukhārī: 1342]
Sayyiduna Jabir bin Abdullah رضي الله عنه narrates that the Messenger of Allah ﷺ said:
"من استطاع منكم أن ينفع أخاه فليفعل"
"Whoever among you is able to benefit his brother, let him do so."
[Ṣaḥīḥ Muslim: 2199]
Yazid bin Asam رحمه الله says:
"We descended into her grave—I and Ibn Abbas. When we placed her (Sayyidah Maymunah رضي الله عنها), her head tilted to one side. I placed my cloak under her head, but Ibn Abbas removed it and placed a stone under her head instead."
[Al-Ṭabaqāt by Ibn Saʿd: 8/110, with a Ṣaḥīḥ chain]
Answer:Yes, a non-Mahram man may also lower a woman's body into the grave.
It is reported that Sayyiduna Abu Talhah رضي الله عنه lowered Sayyidah Umm Kulthum رضي الله عنها, the daughter of the Noble Prophet ﷺ, into her grave.
[Ṣaḥīḥ al-Bukhārī: 1342]Sayyiduna Jabir bin Abdullah رضي الله عنه narrates that the Messenger of Allah ﷺ said:
"من استطاع منكم أن ينفع أخاه فليفعل"
"Whoever among you is able to benefit his brother, let him do so."
[Ṣaḥīḥ Muslim: 2199]Yazid bin Asam رحمه الله says:
"We descended into her grave—I and Ibn Abbas. When we placed her (Sayyidah Maymunah رضي الله عنها), her head tilted to one side. I placed my cloak under her head, but Ibn Abbas removed it and placed a stone under her head instead."
[Al-Ṭabaqāt by Ibn Saʿd: 8/110, with a Ṣaḥīḥ chain]