…if the parents are poor and my husband will benefit etc. so I agreed. May will be 3 years since my husband has been deceased and Allah gave me a good husband and very thankful to Allah for him. But, is it permissible for me to join him in the same qabar? I know his body has been decomposed by now but not the bones which takes like 50 years to turn to dust which is full disintegration. Am I correct?
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It is not permissible to open the grave for this reason.

A person can only be buried in the same qabar with someone else if the body is fully disintegrated. When my husband died the mosque inquired if I want a double depth grave that sometime in the future we can use it to bury a child in it due to poverty…