Muslim

Hadith Commentary:
Vocabulary of the Hadith:
Al-Hamu:
The close relative of the husband,
for example, brother,
paternal cousin,
maternal cousin,
nephew,
uncle,
because, according to Imam Nawawi rahimahullah, by consensus of the linguists,
Aḥmā’,
is the plural of ḥamw (hamu).
By this is meant the relatives of the woman's husband,
for example, his uncle,
brother,
nephew, etc., and by akhtān is meant
the wife's relatives, and the term aṣhār
applies to the relatives of both (husband and wife), and here by hamu is meant the relatives of the husband other than his father and son,
because the husband's father and son are unmarriageable kin (mahram).

Benefits and Issues:
The Messenger of Allah sallallahu alayhi wa sallam has described the hamu as "death,"
because, generally, it is not considered objectionable for him to meet or sit with the woman in seclusion, and under this pretext, sometimes sexual relations are established between the two,
which is the death of the religion of the man and woman,
and if it becomes known, it is a cause for stoning (rajm) for the woman, and if the hamu is married, he too will be stoned, and the husband, out of jealousy,
may even kill them,
or he may divorce his wife,
therefore, seclusion or privacy with the hamu is even more dangerous,
thus, the seclusion of the hamu should not be considered insignificant,
unfortunately, today these instructions are not given importance,
as a result of which regrettable relationships are emerging,
a brother
establishes relations with his brother's wife,
a friend
runs away with his friend's wife,
in this way, families are being destroyed.

Hadith Commentary:
By "hamw" are meant those relatives of the husband with whom marriage to this woman is permissible, such as the husband's brother, nephew (brother's son), nephew (sister's son), paternal uncle, paternal cousin, maternal cousin, etc.—those with whom, in some lawful circumstance, this woman could marry. However, those relatives who are mahram (permanently unmarriageable kin), such as the husband's father, son, etc., are not meant here; it is permissible for them to be alone with her.

Hadith Commentary:
(1)
By "hamw" are meant those relatives who are other than the father and sons, i.e., the husband's brothers, nephews (brother's sons), sister's sons, paternal uncles, maternal uncles, etc., because these relatives are not mahram (permanently unmarriageable kin) to the woman. If the husband passes away or the wife is divorced, marriage with them is permissible.

(2)
The Messenger of Allah (sallallahu alayhi wa sallam) has described these relatives as "death" because generally there is negligence and laxity regarding them, and as a result, dangerous consequences arise. If these individuals are alone with the wife in the absence of the husband, then if the matter is limited to kissing and embracing, it is the destruction of religion, and if it reaches the point of adultery, it is the destruction of life. In this, there is also destruction for the woman, for if the husband finds out, he may divorce her or, out of jealousy, kill her.

(3)
Upon reflection, this hadith can serve as evidence for both of the aforementioned issues.
Wallahu al-musta‘an (And Allah is the One whose help is sought).