I love Hawaii, but know there are better and worse places to stay there also, due to winds, surf conditions, a dump near by, etc. Since they aren’t too picky, I suggest they call a travel agent or two, and get some ideas. The travel agent can steer them to new places, sales or promotions that happen to be going on, etc.
Another option is to check out the various airlines web sites. Sometimes they have sales also. Actually, many years ago, AA had a sale right around either the January or February holiday.