Start with 10% of the DVDs. Look up the current NEW price for each movie (on Amazon.com or ???) Make a list of ALL the titles for sale and prices, post on Craigslist and the trading post. I would price at about 50% of current retail. Offer NO DISCOUNTS unless someone buys 10 or more. "Sorry, this is the first day of the ad, if you want a lower price talk to me in 2 weeks." When the $$$ come in, your husband should be happy, and maybe come up with more titles.
DON'T give them away or sell for pennies. The purchasers will just be eBAYing them anyway.
A huge benefit of downsizing a collection like this is that as you send out the stuff you don't love, you find treasures there. I sent out 50+ books on bookcrossing, and found one treasure I had been "meaning to read" for years. It turns out to be a wonderful, inspiring book:
Elizabeth Ann Scarborough, THE HEALER'S WAR
One possibillity would be to get a giant external hard drive and upload the movies one at a time to your PC. Some software required, I think. If you have not watched it in the past 5 years, you won't miss it too much!