I think you should contact someone who would know more about this than 
anyone on this list unless there is someone on here who works with this on a 
daily basis.  SSDI and Widower's benefits are two different programs.  And 
you usually have to be married for 10 years or more before being eligible to 
draw on a spouse's work record.  I would contact either a Social Security 
lawyer or one of the two blindness organizations to find out what your 
rights are.
Harvey