Hi, muffin! I don't own any of the power functions train (passenger and cargo), but i am a proud owner of an emerald night, which i really love ! As you could already understand, my suggestion is to buy an emerald night to you husband, you won't regret it! Building it is an awesome experience and an interesting challenge, because it isn't a set for kids :) About the tracks i suggest you to buy a couple of 7896 sets (they are perfect for the EN), but if you want your husband run the train without pushing it with his hands, you have to buy: PF XL motor, IR receiver, Battery pack and a controller.
I hope this helped you!
PS: let me say one more thing: your husband sure is lucky!