Is the deceased to be instructed at burial if his body is found after a week?

The basic principle of تلقين (religious instruction/prompting) is that it should occur at the time of death, based on the Prophet's (peace be upon him) saying: "Prompt your dying ones with 'Lā ilāha illā Allāh' (There is no god but Allah)," and his saying: "Whoever's last words are 'Lā ilāha illā Allāh' will enter Paradise." As for تلقين after burial, there is a difference of opinion regarding it, but the preponderant view is that it is permissible, and there is no objection to prompting the deceased after burial, even if the burial is delayed.