You can likely purchase this home without an agent and be "ok" but it's difficult to tell if the listing broker "procured you" - meaning you were made aware that the home was for sale and/or viewed the home based on their marketing efforts. If so, in WA they may be entitled a commission if it's within 6 months or whatever was dictated on the listing agreement. If there was recourse, it would come back to the seller directly, but also indirectly to you because if the seller has to pay the listing broker now and therefore can't offer you the same deal.
Also remember that listings are actually owned by the brokerages, not the listing brokers. If the home is worth enough and there is evidence to show that you knew the home was for sale because of the brokers efforts and the seller was still in the timeframe alotted by the listing agreement, the brokerage could chose to pursue the commission, not the listing broker.
The bottom line is: to be on the smart and safe side, you need an attorney to tell you that you are in the clear. Your wife's friend is likely a good broker and can guide you well on the situation but you really need an attorney. And if they are a responsible broker, they will also tell you the same thing.
I know that saving on a commission is enticing but I truly believe you should have an agent represent you here. Without an agent representing you, it could be a home run but chances are there's going to be a nightmare in there. I am just being practical and basing it on years of experience. There are so many complexities involved in today's real estate transactions that we, as brokers, spend at least 30 hours protecting clients against risk - and that's with our years or expertise! I can't imagine trying to do it with no experience and a full time job. Last year I listed a lawyer's home. I asked him why he listed the home because he could have EASILY navigated the contract himself. His response was, "This is not the situation to be expiramenting in. I understand a contract but you know what could go wrong during a transaction and I need protecting from that. I don't want my sale to fall apart."
Good luck and go get 'em!