Finders fee for freelance design work?

A friend of mine works for an ad agency. He recently had an existing client approach him to design his wife’s business website. The ad agency does not deal with e-commerce – so they were needing to outsource the job and just take a cut of the fees. The client had indicated to my friend that he would be happy for my friend to arrange something outside of the ad agency if the agency did not usually do this work. My friend has then recommended me for the job. He is now asking a 40% cut of the clients payment if I take on the job! I will be undertaking all the work. His role has been simply to refer to me. Most of his communication with the client was as is role at the ad agency. Prior to the ad agency turning away the job he had one meeting with the client – however his role in this was self-appointed and consisted only of him asking a list of questions he asked me to prepare for him, and giving the client a list of my recommendations that I had also prepared (in fact, an email he sent to the client after the meeting was a copy-paste of an email he requested me to send to himself, except he signed his name at the bottom to appear as thought he’d written for the client himself). I’ve not dealt with finders fees before and this is not someone I deal with in business usually – its just a friend. Is it just me or is asking for 40% a joke? I never asked him to find work for me. It was work they simply did not deal with at the agency and that they would have outsourced anyway. Its an existing client so in a way its also a priority for him to service and keep his client?