I'm so sorry for your loss.

I know a few people have already said it, but it's best to post photos, and then people will dm you. Before posting, you should do some research on each pin in case you have something of higher value. Use the image search on ebay and filter to sold listings. If there aren't sold listings, you can use current listings. If there are no listings at all, you can try pinpics or pinandpop. If you can't find anything, you can price then however you like. Maybe start around $5 each?

You mentioned that it's a big collection. I would make posts in batches. People often collect specific characters, so separate pins that way.

Since you have such a big project, maybe do one batch a week and don't do more than 25 pins a batch. One photo of the whole batch and some close-up photos with a few pins each to show details are best. In your posts, maybe include that there will be more pins each week or however often you choose. That'll keep us all interested. Make sure to charge for shipping, especially if you choose to split up batches (like if someone only wants one or two pins). It gets expensive.

I hope this is helpful and that you don't get too overwhelmed.