Loverofcats,
There are sources readily available that may help you. Structure of Magic I and II while technical, can provide a basis for using language to increase the detail of mental maps. I'd suggest rather than using it to elaborate the maps of the problem state, use it to enrich the map about the states you want.
Also, Sleight of Mouth by Robert Dilts is available, as well as Persuasion Engineering by Richard Bandler.
These books provide you with a lot of verbal tools that may help.
Basically, however, simply ask question after question and get more and more sensory specific with your questions. "How do you know that" is a good question to use about anything. "What do you feel? What do you see? What do you hear? How do you know *that* is true?"
How specifically do you think increasing your husbands maps in what ways will help? Is he having problems with basic cognition?