but are the occupants of the graves addressed as a stone is addressed, or as one who can hear?
The answer is that the latter is apparent—that is, they are addressed as those who can hear.
Ibn al-Qayyim mentioned in his book al-Rūḥ (1) a hadith from the Prophet ﷺ: “Whenever a Muslim passes by the grave of a brother whom he knew in this world and greets him, Allah restores his soul to him so that he may return the greeting.” Ibn Abd al-Barr declared it authentic, and Ibn al-Qayyim endorsed his assessment. Thus, it is not far-fetched that the occupants of the cemetery generally hear when they are greeted. We should not compare them to the Black Stone, for we have tangible sensory evidence that a stone does not hear—namely, that it is a stone. Yet even a stone may hear as well. Allah the Exalted says concerning the earth in general:
“On that Day it will recount all its news, for your Lord will have inspired it.” [al-Zalzalah]
“It will recount all its news,” meaning the good and evil done upon it, whether audible speech or visible action; it will relate it on the Day of Resurrection. The skins will speak, made to speak by Allah, who has caused everything to speak. So do not regard such matters as improbable, for the human mind cannot encompass the power of Allah.
Therefore, it is not far-fetched that, when you say to the occupants of the cemetery, “Peace be upon you, abode of a believing people,” they hear. As for Allah’s saying, “Indeed, you cannot make the dead hear” [al-Naml: 80], this refers to those whose hearts are dead; for the Prophet ﷺ would not go out to the occupants of the graves to call them.