As a former seller of used books who still has a lot of inventory, I can tell you what will probably happen to them. Unless you will them to someone special who really wants them, they will either be donated to a thrift shop, tossed in the trash, or given to someone like me who will come get them and then try to sell them. Then they will sit in storage until that bookseller has time to list them to sell online, finds room on shelves for them in a physical store, or donates or trashes the rest that have little resale value. My garage and half my house is full of books that people gave me after their parents died.
I think I’ll have a party one of these days soon and invite my friends to take what they want now from my shelves unless they are books I know I want to keep reading in the few years I have left. Then I can let people claim the ones they want me to leave for them after I die. I’d rather see true friends start enjoying them when I’m still alive.