What are the husband's rights over his wife after his death?

If the husband dies, the marital عصمة (bond/authority) ceases, except concerning the waiting period ('iddah), which is four months and ten days for a non-pregnant woman, and until delivery for a pregnant woman, as per Allah's words: "And those of you who die and leave wives behind them, they (the wives) shall wait (as regards their marriage) for four months and ten days." (Quran 2:234) and "And for those who are pregnant, their term is until they deliver their burdens." (Quran 65:4). As for general rights like supplication (du'a) and seeking forgiveness (istighfar), these remain, as Allah says: "Our Lord! Forgive us and our brethren who have preceded us in Faith." (Quran 59:10).