What is the ruling of Islamic law regarding goods left by a husband as a trust with his wife and her family, then he died without knowing if he had settled his debts or divorced his wife, and he instructed his wife not to hand over the goods to his children?

The goods belong to the deceased and are an inheritance to be distributed among the heirs. The most that happened is that he advised your mother not to give them to his children. His children should be consulted to ascertain whether the man divorced your mother or not, and what wealth and debts he left behind. If his estate is known, and it is clear that the marital bond remained, then your mother's share, which is one-eighth, can be determined. If the heirs withhold her right, she should take from the goods an amount equal to her share and return the remainder to them. If his wealth is insufficient to cover his debts, the goods must be revealed and the debt paid from them. If it becomes clear that a divorce occurred not during a death-sickness, then your mother has no inheritance, and she must return the goods to his heirs. In case of dispute, the Sharia court is the reference. If the marital bond remained, your mother must observe the 'iddah (waiting period) of four months and ten days for the death.