If someone dies and i'tikaf was obligatory on him, what should be done?

Hazrat Laith narrates that Hazrat Tawus was asked about a woman who had passed away; she had made a vow to perform i'tikaf in Masjid al-Haram for one year. She had four children, each of whom was willing to perform i'tikaf in her place. Hazrat Tawus said that all four should perform i'tikaf for three months each and also keep fasts.

Hazrat Hakam states that the missed I'tikaf of a deceased person will not be made up.

Hazrat Ubaidullah bin Abdullah bin Utbah narrates that my mother had made a vow to observe i'tikaf for ten days, but she passed away and could not observe the i'tikaf. Hazrat Abdullah bin Abbas (may Allah be pleased with them) said: Observe i'tikaf on behalf of your mother.

Hazrat Aamir bin Mus'ab narrates that Hazrat Aisha (may Allah be pleased with her) performed i'tikaf on behalf of her brother after his passing.