What will happen if my attorney recently died and my sentencing is scheduled for next month?

Eventually, you may be able to have the attorney's estate or business cover the costs of another attorney. Unforutately, it is very unlikely this is going to happen before your hearing.  The prosecutor will most certainly honor the plea agreement. It appears you are at the end of the process, so there is little that is required of an attorney. First, I would try to contact anyone that was associated with the deceased attorney (e.g. secretary, paralegal, or anyone answering his phone) to find out the situation. If this does not result in any resolution, I would call another attorney to be present at the sentencing hearing and help you with dealing with the deceased attorney's affairs (it shouldn't cost you much).  Good Luck.