The rules of disinterment are quite strict (see SA YD 363:1), dinonline has a good summary. The case you ask about is not part of the list, nor are there any cases of pressuring a family member. A beit din would have to be asked but the "burden of proof" appears much higher than a delayed burial.
Several exceptions to the prohibition are mentioned by the Shulchan
Aruch (Yoreh De’ah 363:1). It is permitted to excavate and remove
remains for the following reasons:
- If they were buried there without the permission of the landowner.
Under such circumstances, it is a mitzvah to do so (see also Birkei
- If the grave and remains are likely to be damaged by water
or sewage backups, by vandalism, and so on, and there are no
alternatives to removal that could solve the problem. This was the
reason given by Rav Ovadyah Yosef (Yalkut Yosef, Aveilus 32:9)
concerning relocating graves in territories that were returned to
Egypt under the Camp David accords.
- If the person was buried in one
place with the specific intention of later removing his remains to a
- If the remains are being relocated to the Land of
Israel, or to the family burial plot (kever avos). See Iggros Moshe
(Yoreh De’ah 3, no. 153), who writes that decisions on relocation of a
grave can only be taken by the children of the deceased, and not by
the general Jewish community. Another reason for permitting the
relocation of a grave is when the current position causes damage to
other graves (see Eretz Chaim, Yoreh De’ah 364).
The Shulchan Aruch (Yoreh De’ah 364:5) further rules that a grave that
causes damage to the public may be removed, even if the burial took
place with the consent of the owner of the property.
We learn from this halachah that the imperatives of kevod hameis yield
when they unduly impact the rights of the public to access and use of
the property. Rav Moshe Feinstein (Shut Iggros Moshe, Yoreh De’ah 3,
no. 151) writes that there is room to distinguish between a single
grave and an entire cemetery. However, most authorities specify that
the law permitting relocation applies not only to a single grave, but
even to an entire cemetery (Rav David Oppenheim, cited in end of Shut
Chavos Yeir; Shut Rabbi Akiva Eiger, no. 45).
The application of this halachah will depend on how we define damage
to the public, and this depends on the particular circumstances and
the approach of the specific Posek involved.
See also here.