When I applied for probate for my dad earlier this year, his executors were myself and my daughter. On the probate form it asks which executors are named on the will and if they are not all applying for probate what are their reasons and there are three choices a) deceased b) doesn't want to be an executor at the moment but reserves the right to change their mind and c) gives up the right to be an executor. It wasn't convenient or necessary for my daughter to be involved so we put that she didn't want to but reserved the right to change her mind just in case anything happened to me before everything was sorted. So your husband's remaining executor(s) can carry on without the deceased chap.