But if anyone fears partiality or wrong-doing on the part of the testator, and makes peace between (The parties concerned), there is no wrong in him: For Allah is Oft-forgiving, Most Merciful.
According to the Study Quran,
This verse addresses the possibility that a testator might act
prejudicially with regard to his heirs through manipulating his bequests. For
example, he might make a bequest to his daughter-in-law with the intent of
enriching his son, which would violate the rule that legal heirs cannot receive
bequests (Q). A ḥadīth states, “Injustice [janaf, the same word as in this verse] in
the matter of bequests is a major sin [kabīrah].” It is the duty of the community
to adjust or cancel such bequests when it becomes clear that their intent was to
circumvent the Quranic laws of inheritance (Q). Them refers to the heirs, and
him to the executor of the estate, the witness of the bequest (as required by
5:106), or whoever has this responsibility (R), although some seem to place the
responsibility on the heirs to address this question (Q). There is no sin upon him
in such a case because, although altering a bequest would ordinarily be a sin, in
this case justice overrules the instructions of the testator (R).
Nasr, Hossein (2015). Study Quran. http://www.islamicweblibrary.com/wp-content/uploads/2020/04/TheStudyQuran.pdf