I am very sorry for your loss. The lawyer can not hide or destroy the trust instrument as that would be a violation of the attorney's ethical and professional obligation subjecting him or her to discipline. The irrevocable trust would have a separate tax id number. The trust would have a much higher tax rate than your husband's individual tax rate. For this reason, income typically would be distributed to your husband annually to obtain a distribution deduction at the trust level. Review your prior income tax returns for income from the trust. You could also of course make a written request to his mother and the attorney especially of the attorney also represented your husband. Note that while you refer to yourself as the only surviving heir, the trust itself will control who will receive any distributions. Trusts are often written with an intent to provide distributions to blood relatives to the exclusion of spouses. You may also seek to conduct public record searches for other assets that could be linked to your jusband. Many attorneys have access to public records and my be able to conduct a search for you. Once again, I am very sorry for your loss.
Once you are appointed as fiduciary of your husband's estate you will have all legal authority to turn over every rock to search for assets or information needed to collect all property your husband had any interest in. But it takes experience to know how to go about this; there are a dozen different avenues and sometimes you have to go back to court for special authority to get certain types of information. You need an experienced and aggressive probate lawyer on your side. Filing the papers is the easy part; the family is going to walk all over you until you realize you have to hire a lawyer. The longer you wait, the more likely it is that the family will be successful in hiding and transferring assets.
Your best bet, based on your fact pattern, would be to retain a trust attorney for assistance. That being said, it is possible that the trust you are searching for may provide for the exclusion of spouses as beneficiaries (the beneficiaries and contingent beneficiaries can be specifically defined). You need to consult with a local attorney to go though all of your facts and circumstances to determine the best method to proceed.
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