If you are interested in helping out this family, I suggest you do an end-run around your husband's "heroism," and contact them yourself. Develop your own relationship with them, check in with what they might need, and then you are all clear: this is you, helping out a family in need while your husband is out of town. Or, contact them and tell them yr. husband committed you w/o checking & see if they can make other arrangements, as your husband is not planning on fulfilling the commitment himself.
The best solution to a narcissistic A is to NEVER let them be an intermediary in your relationships. They lie, distort, manipulate and charm.....and end up looking amazing while everyone else seems like lesser beings. Frustrating, but if you keep checking in with the other people, the frustration will disappear. Well, for a moment at least!