Q. Can a living spouse give ghusl to a deceased spouse?
A. If the husband passes away, the Nikah of the wife to the husband fully terminates after she completes the Iddah period of 4 Months and 10 days or until birth if she is pregnant. At that point, she is not at liberty to marry another man until she completes her Iddah period. Therefore, it is permissible for her to give her husband Ghusl after his death.
On the other hand, if the wife passes away, the Nikah of the husband to the wife immediately terminates. At that point, the man is at liberty to marry whomsoever he wishes. Therefore, it is not permissible for him to give her Ghusl after her death. (Hindiyyah 1/160)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa