The baseline halacha is that a body may not be moved from grave to grave, even from a disgraceful to an honored one, but an explicit exception is made for burial among one's own family and for transfer to Eretz Yisrael, since Arukh HaShulchan (Yoreh De'ah 363:1-2) and Shulchan Arukh (Yoreh De'ah 363:1) both state that it is pleasant for a person to rest near his family, and that moving a body from outside the Land to Eretz Yisrael is permitted, citing the pasuk 've'chiper admaso amo.' The Beit Yosef and Bach record the same ruling, noting the Rashba's case of one who ordered burial among his ancestors and whose sons were obligated to fulfill his wish, and the Rambam likewise states that a body may be moved into one's own family plot even from an honored grave to a less honored one (Beit Yosef (Yoreh De'ah 363:4), Bach (Yoreh De'ah 363:1-2), Mishneh Torah, Mourning 14:15).
The Gemara in Ketubot 111a:9-10 establishes the special merit of burial in the soil of Eretz Yisrael, teaching that one buried there is considered as though buried beneath the altar, which underlies the leniency to transfer a body there even against the ordinary prohibition on relocating the dead.
Modern poskim stress that the halachic basis for any such transfer is the benefit and honor of the deceased, not the convenience of the living: B'Mareh HaBazak Volume VII 80:6 states plainly that the permission to move a grave rests on what is comfortable and fitting for the dead, not on the wishes or convenience of surviving relatives, who are in fact obligated to set aside their own preferences for the sake of the deceased's honor, and B'Mareh HaBazak Volume IX 40:17-18 similarly affirms that it is a mitzvah to bring remains from outside the Land to Eretz Yisrael.
Several sources explicitly caution against building a leniency on the family's desire for future visitation: Shaarei Halacha uMinhag (Yoreh Deah 131) records the family argument that they will not be able to visit the grave on the yahrzeit, and the parallel case in Igros Kodesh letter 6484 discusses a near-identical scenario where family members object to a reburial precisely because they fear they will not be able to visit the grave on the yahrzeit, directing such a question to a local rav who can hear both sides and stressing any condition made at the original burial.
Nitei Gavriel, Aveilus vol 1, perek 131 frames the general rule that a body should not be moved from the city of burial if a cemetery was available there, but permits transfer when the deceased explicitly requested burial elsewhere, including in Eretz Yisrael or near ancestral graves — making the deceased's own wish, rather than the family's practical concerns, the operative criterion, a point echoed by Igros Moshe YD 1:237, which favors burial with one's ancestors in principle but voices real uncertainty about moving a parent specifically to the plot of a spouse and children, counseling that relocation be avoided where possible or at least delayed until only bones remain.
Igros Moshe (YD 2:156) addresses a case closely parallel to the present one — sons wishing to exhume their mother's remains and move them to the plot their father purchased and where he was later buried with a son — and considers whether this may be permitted on the reasoning of the Or Sameach, treating the question as a live halachic inquiry rather than a settled matter.
Tzitz Eliezer (11:75) holds that a person buried outside Israel gains real merit from having the body reinterred in the Land, and that heirs are bound to carry out any explicit burial instructions the deceased gave, assigning particular significance to burial in Jerusalem specifically; in Tzitz Eliezer (18:71) he further rules that exhumation and reburial in Eretz Yisrael, particularly Jerusalem, can be a mitzvah even without an explicit request from the deceased, and some authorities permit it even against an expressed wish not to be moved.
Other sources on the sheet illustrate how later poskim weigh competing practical concerns in such relocations without resolving the present family's specific motive: B'Mareh HaBazak Volume II 90:4-6 discusses a woman who purchased a plot beside her husband in Israel precisely so her children could visit without constraint, finding no explicit ruling preferring burial abroad for visitation over burial in Israel, while B'Mareh HaBazak Volume I 73:14-16 counsels leaving a body in its current grave where the actual exhumation would involve disgrace to the deceased or where other practical factors favor non-disturbance, and Tzitz Eliezer (7:48) rules that transfer to Eretz Yisrael is permitted and that heirs may even be obligated to fulfill the deceased's request without delay.