Selling brand new wigs
There are a couple of FB groups which allow you to sell wigs. You will need pictures (at least 1 or 2 of each wig) a brief description, brand name, style name, and color for each wig you list. It's a very simple process but may get very tiring trying to sell so many. If you aren't in a hurry maybe you could try listing just a few at a time. The wig groups are Flip your wig, yes its a wig, and there are others. Join a couple and look around.
Also, have you tried reaching out to other retailers to see if any of them would like to purchase the inventory?
I'm very sorry for the loss of your mother and hope staying busy with this project helps you keep yourself grounded.