The durable power of attorney is no longer effective because it ends upon the death of the principal. The trust should say who will serve as successor trustee and who will receive the trust funds upon your sister-in-law’s death. If no successor trustee is named in the trust, your husband may have to go to court to be appointed as trustee. A local estate planning or elder law attorney can review the trust and advise you and your husband on the necessary next steps. You can find a qualified attorney in your area here.