From my friend:
Restaurants:
Pied de cochon
Club chasse et pêche
Europa
Joe Beef (or its often less-busy and imho cooler counterpart: Liverpool House)
Toqué
Garde-manger
Salle à manger
Les trois petits bouchons
Quartier général
Kitchen Galerie
Tapeo
Pub Dominion
... to name a few.
Basically the first five are pretty expensive (esp. Europa), and by far the best and most well-known restaurants in Montreal. I've only been to Pied de cochon and Liverpool, personally, but I know of friends who've been to the other three and loved them. If I'd recommend any out of the five, it would be Pied de cochon. The chef who owns it basically took traditional poor-man's Quebecois cuisine (stuff like poutine, pork n' beans, maple-syrup-based stuff) and made it new and interesting and gastronomical. He should try the foie gras poutine for sure if he goes (get one plate for two peeps as an appetizer... and know that their cooking is very meat-based... meaning you might just get a slab of meat. So talk to the waiter to make sure you know what you're getting into).
The other ones are more bistro-type places. Meaning slightly cheaper, but still great dinner experiences. I've been to all but Kitchen Galerie, Tapeo, and Garde-Manger, but they are all apparently great (my chef-school friend worked at Kitchen and currently works at Tapeo... which is tapas, btw). I have a slight preference for Dominion, cuz' I love the décor and ambiance (it's basically pub food made fancy), but really any of those would be good options. Oh, and there's totally a place we've been meaning to try as well! It'll likely be our next fancy-dinner-night if we ever get out of the house again.

It's called Manitoba, and it's basically very umm... salt-of-the-earth-y. It's essentially local produce and local cuisine... like... native cuisine almost. Well I'll let the website describe it, I guess, but it sounds very interesting, and it's been getting great reviews from what I know:
http://restaurantmanitoba.com/?lang=en#contact
In terms of location, Club Chasse et pêche, Europa, and Toqué are all in the old port, as is Garde-manger. Dominion is downtown. Pied de cochon, Salle à manger, Trois petits bouchons and Quartier général are all in the Plateau, and the final three (Tapeo and Kitchen Galerie... and Manitoba) are further north in Villeray. All are accessible via metro.
As for places to go to for shows... if he likes the jazz/blues stuff, there's a place called The Upstairs (don't be fooled! it's actually a basement!), located downtown. It's a quaint little jazz bar. I think I've been once. There's also the House of Jazz (also downtown) which might be cool, but I do believe it's a bit more touristy. As for rock shows, he'd really be best to check what's playing on the weekend he'll be down. Good promoters to check out are
Evenko.ca and Blue Skies Turn Black (
http://www.blueskiesturnblack.com/)... the latter being for more indie stuff. There's also La Vitrine that he should check out while he's here. It's basically a ticket sales place, so he could go online (
http://www.lavitrine.com/?lang=en) or even just pop in one afternoon and see what's happening on that particular night. They're located on St-Catherine and St-Laurent, so you can't be much more central than that.