Okay @goose, you may be in luck. There is a very reputable record collector and Vinyl Community YouTube video maker named Norman Maslov (with I believe about 20,000 subscribers). When a dear long time friend of his passed away a few years back the fellas wife sold his record collection to Mazzy (the name Norman answers to) and another friend of the fella, and Mazzy held a number of auctions live on YouTube, selling the titles Mazzy and the other friend didn’t want to keep and add to their own collections (Mazzy has I believe around 6000 LPs).
After that a record collector in the Seattle area contacted Mazzy to inquire as to his interest in auctioning that guys LPs. Mazzy was, and held another bunch of auctions live on YouTube. Mazzy might be willing to do the same with your friends collection.
Mazzy moved to Seattle 12 years ago, after living and working in San Francisco his entire life (he had his own business, representing photographers in commercial enterprises). You can contact him through any one of his YouTube videos. Do a search on the YouTube website for Norman Maslov.
When I place.a vintage drumset for sale in one of the good drum shops I have a relationship with (Professional Drum Shop in Los Angeles, Revival Drum in Portland Oregon), I give them a 20% commission, which works well for both myself and the shop.
Perhaps you and Mazzy can agree to some sort of arrangement. Mazzy retired a while back, and now has free time on his hands. He is also fairly knowledgeable about Jazz music and Jazz LPs, and has a very good reputation. I trust him---Eric.