If you're on a 7 nighter, skip the suit (or sport coat) and bring a dress shirt and tie. Much less room in the suitcase, a lot more comfortable to wear and it's easy to ditch the tie (put it in a pocket) after dinner if you are rushing off to see one of the many shows that take place in the evening. Dress shirt, tie, slacks and sandals are my formal attire. Other nights I replace the dress shirt and tie with a polo shirt.
And no, you/he won't feel out of place. Contrary to many peoples opinion, it will not ruin the dinner for you and EVERYONE else in the restaurant.