How is inheritance divided in Islamic Sharia if the husband dies, taking into account that some of the money is invested from the joint income of the spouses, and that some of the assets were owned by the husband before marriage, and do the wife's children from her previous husband have a share in this inheritance?

If a husband and wife share assets and one of them dies, their share is divided only among their heirs. If the husband dies, his share of the shared assets is divided between his wife and his son, and his wife's children from a previous marriage do not inherit from him. If the husband bequeathed to his wife's children an amount equal to his son's share, this is a bequest exceeding one-third (of the estate) and is contingent on the approval of the heirs. The heir-son may refuse to give his step-brothers what exceeds one-third. A bequest should not exceed one-third of the wealth when there is an heir, and any excess is dependent on the heirs' permission.

To fulfill your wish for your children, there are two ways: 1. That each of you manages your own wealth independently, knowing the amount of wealth each party possesses. If you die, all your children will inherit from you equally. If your husband dies, only his son will inherit from him, and he may bequeath one-third or less to your two sons. 2. That you divide the money, or a portion of it, among the three children as a gift, on the condition of actual possession and ownership, such as depositing the money into their personal accounts or their guardian taking possession of it on their behalf.