I am not admitted in Washinton. It appears that you may have confused two very different and distinct "jobs" here: one as executor and one as contractor for repair of the home.

An executor - or personal representative - in the state of Washington is paid either in accordance with what the Will states or the amount determined by the Court to be "reasonable and just."   The Court takes in to consideration various factors which include the type of services performed as well as the value of the estate assets. 

I would see if your brother is intending on being compensated for the work performed to update the home himself under the heading of personal representative or he is going to pay himself as if he hired an independent contractor to make the house ready for sale.  I would check with the estate attorney if there may be a conflict here in doing the latter. 

I am licensed in Washington.  In fact, executors can be paid; a sum as stated in the will, or the "reasonable value" of his/her services as set by the probate department.  I'm an attorney and, at this very time I am the Trustee of a friend's post-mortem children's trust.  I had an agreement with the deceased that I would be compensated at my usual and normal - and monthly I pay myself from the trust account.

If there is no payment provision in the Will, you can ask the court to review what this person has done  - maybe he's taking too much under the "reasonableness" standard.  Good luck to you.