Is there a way to appeal a decision for widows benefits? My husband and I were together for 10 years but only married 5 days before he passed.?
Yes. First you need to file an application for widow's benefits, and then if your claim is disallowed you would have 60 days in which to file an appeal (https://www.ssa.gov/pubs/EN-05-10041.pdf).
Just for the record, though, you must normally be married for at least 9 months in order to qualify for widow's benefits. So, unless your relationship prior to your marriage ceremony could qualify as a common law marriage, it sounds like you would have to meet one of the exceptions to the duration of marriage requirement in order to potentially qualify for widow's benefits. The most common exception to that requirement involves accidental deaths, but there are other less common exceptions. For more information regarding exceptions to the 9 month duration of marriage requirement, refer to the following sections of Social Security's handbook: https://www.ssa.gov/OP_Home/handbook/handbook.04/handbook-0401.html & https://www.ssa.gov/OP_Home/handbook/handbook.04/handbook-0404.html.