You do not need to have two executors to a will. If the will sets up a trust fund then it would be necessary for there to be two trustees to be able to give a valid receipt for capital money, but even if that is the case the sole executor would be able to appoint someone else to be trustee with him. In fact even if the will appointed no executros, or all the named executors die, then the will remains valid. Someone would need to obtain the "letters of adiminsitration" from the probate court, "with will annexed", and there is a pecking order of who can apply. Is that enough for your purposes?