ENTIRE SYSTEM NEEDED TO SELL

Go ahead and list the components and we may be able to suggest what you might expect to receive if you want to go to the minor chore of listing them or putting them up for auction... or let us know (generally/city) where you are and perhaps someone like Grannyring- who I know to be trustworthy- (as would anyone with lots of posts & great feedback) to be helpful in at least pointing you to an honest dealer. You can also pay a bit and utilize the "Audio Bluebook" function on this site. In general, you'll probably get about 50% of new value. You can lookup new prices by just Googling the equipment name/reviews. But consider this.....
As Tom6897 suggested, consider passing it along to his favorite relative/nephew who would appreciate it and always remember your husband/and you. Here's the advice I got from a quality gun dealer when I considered selling my (alzheimer's) father's very nice heirloom shotgun: 
He said, "One day your father will be gone, the shotgun will be gone, and the money will be gone." What a good dealer to convince me to keep it.

Michelle,

My condolences to you & your family.

Regardless of whether you find a dealer to sell on consignment or you sell here, you do yourself a huge disservice by trying to sell the system as a bundled package. It's easy to tell yourself that said plan would "make it simpler", but the reality is that packing and shipping will be the same work either way. The key is that this is a hobby of putting together puzzle pieces and the vast majority of potential buyers don't buy more than one piece at time. That's a combination of cost and a desire to understand each items impact before making another change. By selling a whole system, you eliminate >90% of potential purchasers. With such a small number looking to buy a whole system, you will end up taking far less than value or not finding a buyer. 
Generally speaking & oversimplified to give you an idea:
used gear sells for ~50% of MSRP. Dealers who buy wholesale will pay you ~20-25% so they can resell it for 50-60%. Selling each piece individually here might yield double the proceeds. 
There is also on this site a "blue book" you can subscribe to that tracks sale prices of gear. Last I saw it cost $50 to subscribe, but if you have a lot of pricey gear to sell, it might be worthy of consideration. Cheers,
Spencer

Michelle-

condolences to you and your family during this time.
Another agreement for obtaining a dealer/retailer to consult you and selling the system.  Keep me posted.

R.I.P. Mr. Parsons.

I have a different take.
Unless you really need the money - give it away to someone who will appreciate it and keep your husband's audiophile legacy.