From your comment which is hard to find so I have copied it here:
<<both parties were married, lady died and left her son her house from a former marriage, she also had bank accounts which he emptied and moved money to his accounts. leaving her husband with nothing. They were both executors but in the will only the house was left to him. What can my brother do>>
I presume 'brother' is actually husband. Let's take this one step at a time (UK law):
1. If deceased had a house titled in just her name and son was her sole heir, the house will pass to him through Probate if there is enough money in the estate to pay IHT and any other debts. Otherwise the house may need to be sold no matter what the will says because debts come before distributions under the terms of the will.
2. Neither son nor husband were entitled to touch the deceased's bank accounts except those in joint names. So husband can continue to use a bank account that is in husband and deceased's joint names and son can use a bank account that is in son and deceased's joint names. This is a strategy that is often used to protect the estate during Probate. For example it can be used to allow utility bills to be paid.
However, careful records need to be kept as that will be part of the estate. If son is on the bank account and has emptied it, that will come out of what he inherits since he was not entitled to any of it, (I am assuming that son did not put some of his own money into that bank account). Probate will protect husband as long as he has kept careful records because house will not be transferred to son unless this is cleaned up first.
You have to wonder how son was able to transfer assets to another account. Both executors broke the law if they did not inform the bank of the death of the account holder.