No, an inheritance from your brother is not taxable. The U.S. does not have a a federal tax on inheritances.
Since this is a foreign inheritance, there may be additional filing requirements required to report this foreign inheritance to that IRS. Only foreign inheritance or gifts over a certain amount threshold would require a Form 8938 - Statement of Specified Foreign Financial Assets and/or a Form 3520 - gift or inheritance from a foreign person (nonresident alien) or from a foreign estate and the total amount during the year exceeds $100,000.
If your U.S. state of residence has an inheritance tax, it is possible there may be a state tax obligation. That would depend on your state's tax law (if any). See: Does Your State Have an Estate or Inheritance Tax?