Responsa for Bava Batra 273:11
אמר רבי זירא א"ר יוחנן הלכה כרשב"ג ואפילו היו בהן עבדים והוציאן לחירות
[or] 'Here is thy divorce after [my] death', [the divorce in all these cases] is invalid.<span class="x" onmousemove="('comment',' Lit., 'he said nothing'. because he meant that the divorce shall not become effective except when he died, but after death one cannot give a divorce similarly, in the case of the gift of a dying man, possession was meant to be acquired after and not in death. ');"><sup>30</sup></span> R. Zeira said in the name of R. Johanan: The <i>halachah</i> is according to Rabban Simeon b. Gamaliel and even if the estate contained slaves whom he liberated.<span class="x" onmousemove="('comment',' The liberation is valid. ');"><sup>31</sup></span> [Is this not] obvious? — It might have been presumed [that] he could be told that it was not given to him for the purpose of doing what was prohibited,<span class="x" onmousemove="('comment',' It is prohibited to liberate a heathen slave. Cf. Lev. XXV, 46. ');"><sup>32</sup></span>
Teshuvot Maharam
A. Since C did not marry before A's death, and since the money never came into C's possession, it never belonged to C, and A's widow is, therefore, entitled to collect her ketubah from that money. A widow is entitled to collect her ketubah from all bequests made causa mortis, and from all gifts that are not legally to be delivered to the donee (as in cases where the donor died before the stipulated date of delivery of the gift) but which must be so delivered for the reason that "it is a meritorious act to fulfill the expressed wishes of a dying person" (Gittin, 15a).
SOURCES: Pr. 966; Mord. B.B. 629.