There is an effort versus reward consideration here. Chances are that the most money could be made by selling in suitable lots on eBay, but it could be a lot of work. In contrast, selling a collection to a commercial figure trader should be less hassle though they’d be sure to drive a hard bargain as they’ll want to turn a decent profit themselves.
A couple of other thoughts. One, did you colleague’s husband have a circle of gaming friends who might be interested in buying figures or willing to help move the collection on? Two, some auction houses will accept gaming collections and might be worth considering. I’ve seen some good prices achieved at auction though the seller’s fees will take a chunk. Auctioneers sometimes have strange ideas on appropriate lots though.