I have to finish a few thousand 45 years?

My father has been a DJ for about 40 years. It has accumulated about 3000 probably 45 of all genres, and about 500 78. What is amazing is that they are all perfect. No scratches, brand new look sleeves. He is interested in selling. I mean someone they like to get their hands on this collection. There are plenty of rare elements. My question is, does anyone know of a specific auction that deals with music.

A quick Google of "music auction" appears a few results. However, you can try to contact an old record seller in your area to see if they have any suggestions before trying anything online.

Heritage Auctions (HA.com) – Highlights of the 2009 June 5-6 Music & Entertainment Auction