Depends on what he's looking for. Joe Beef is a must, no matter what the circumstances are.
If it's a night for a group of people and they're not planning on being loud/boisterous, then Tuck Shop (I know that you can have private parties there, it's not a super big place), Milos, Park, L'Expresse, Lawrence, Au Pied de Cochon... If they're not from Quebec, send them to Au Pied de Cochon and tell them not to eat lunch. They'll thank you later.
If they're into Wine Bars, Le Vin Papillion & Mon Vin Lapin are both owned by the same people as Joe Beef & Liverpool House and are supposed to be fantastic. They take no reservations, mind you.
If they want a fun place for cocktails, Distillerie #1 (Has 2 locations and both are pretty close to cheap eats before/after).
If they want good food that won't cost them an arm, there's Ma Poulle Mouillé (Portugese chicken joint) and La Banquise (Poutine joint) that are across the street from each other. Don't go to La Banquise at 6pm, you'll be waiting a while to get in.
Depending on what he specifically wants (type of food, price, ambiance, etc) I can give other suggestions.