Yes there is. Your Will needs to have language that essentially creates a Trust at your death instead of leaving everything to him outright. Whatever your son would inherit from you would go into this Trust and it would be protected...only if the proper language is present. I would recommend having your Will reviewed by an experienced Estate Planning attorney to make certain that your wishes are put in place properly.
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Leave the funds to your son in trust. That way your son never takes possession of the money. You can then leave contingent beneficiaries in the trust to address the situation of your son's passing. The trust should not be subject to any marital property division.
I would retain an attorney in your area to properly set up your estate to ensure you are protected from this situation.
This answer does not, nor is it intended to, create an attorney-client relationship or constitute attorney advertising. Rather, it is offered solely for information purposes. Since the facts of each case are different, it is critical to consult with qualified counsel with whom information can be shared and assessed under an attorney-client privilege, so that competent advice can be obtained on which you can make informed decisions.
You could leave your assets in trust for your son and, if it has the proper language, such assets, while in the trust, would not be taken by your son's spouse. Another option is to form an entity (such as a LLC), transfer certain assets into the LLC and put that into the trust. Under state law ownership in LLCs cannot be "taken." You should seek the advice of an estate planning attorney in your area.