Not enough information to know. It depends on what the income consists of, and how the trust is treating it. If the money is income to the trust, and the trust is passing through both the income and the tax obligation, then the tax treatment is based on whatever generated the income: capital gains, qualified dividends, non-qualified dividends, ordinary income, etc., etc., etc. It is possible that the trust will pay any tax obligation, but because trust rates are generally much higher than rates for individuals, if the trust is allowed to pass the tax obligation to the beneficiary, it will generally result in a lower tax liability for the amount of income generated. On the other hand, if the money is not taxable - income from tax-free bonds, etc., the trust may be able to pass the money on with no tax obligation. Or if the money is actually part of the inheritance, with no gains or losses, there would also be no tax.
You really need to ask her step-brother these questions. As the trustee, he is the one who is responsible for issuing the K-1 that she will get each year. The K-1 is what will tell you how to put the income on your tax return.
AJ