Do the grandchildren get anything from the estate due to the law of binding wills (wasiyah waajibah)?

Ruling on allocating part of the estate for sponsorship of orphans

He died and left behind a mother, a father, a wife, nine sons and six daughters

He gave his mother a gift then she bequeathed it to him after her death

He died and left behind a wife, three sons and five daughters

Their mother prevented them from taking their share of their father’s estate, and issues concerning the fairness of giving (to one’s children)

He died and left behind a wife, two sons and three daughters

His father gave him something then he died before the son took it

He died and left behind a wife, four sons and four daughters

If there is only one relative, he takes the whole estate