Allison, does your father socialize much? Does he have a group of poker buddies or friends to golf with, or something on that order? What helped my mother a lot after my father's death was belonging to a close-knit neighborhood & her having stayed in touch with former coworkers from the job she'd retired from years before. She's always been gregarious, while my father was a little less so; she ran their social life. Still, her life had recently revolved around caring for him while he was ill, so at first she faced a great emptiness & had to remember what life was life before she became a nearly round-the-clock caregiver. Nearly three years later, she's still adapting. I hope your father has a lot of social contact to help with this loss.
Michele, I've been to Vegas on several occasions -- my company used to like to hold a huge annual offsite meeting there, taking over the Rio, a casino & hotel that's off the strip -- & I have never gambled even a cent.
I used to hate, hate, hate it, until my L.A. friends told me to show up early & met me there, and we hung out together for a few days before my working meetings started. They made me like Vegas a lot more. But to appreciate "their" Vegas, one has to have a sense of humor, a relish for kitsch & camp & an appreciation for bygone Americana from 1940s-1980s.
First thing I do when I get there is sign myself up for some spa treatments, as there are lots & lots of day spas connected to the hotels & elsewhere.
Then I go to the shops at the Venetian, to visit the Acca Kappa shop, which sells wonderfully subtle scented Italian soaps & toiletries. (Black Pepper is one of my favorites by them.) I don't know why they don't have a free-standing store in NY, but they don't.
Then I make a pilgrimage to Hoover Dam, which is thrilling to look at. First time my L.A. friends drove me out there, I thought, "Big deal, a dam. Holding back water. Okay, so I'll go look at a public infrastructure work." And oh, was I ever wrong. It was spectacular & awesome: Turns out that I do give a dam. They were putting up a bridge right near the dam, and I'd like to see the finished bridge, which also looked like an engineering marvel.
Another favorite place is the Boneyard, where the retired neon signs are sweetly sleeping, commemorating Las Vegas history. Bring your camera to take pictures of yourself near the neon cowboys & etc.
http://www.neonmuseum.org/the-boneyard.html
Also, I keep meaning to sign up for a day trip into the Grand Canyon from Vegas, but haven't done so yet.
And the other thing is that Las Vegas is like Broadway West. A lot of shows transfer out there after they finish running in NY, or have a production there simultaneously. So look into that early, so you can strategize your ticket-buying to find the best price for seats.
I also recommend getting a drink with an umbrella in it at Frankie's Tiki Room.
http://www.frankiestikiroom.com/
And finally, Saef's L.A. Friends' Favorite Place in Las Vegas, Peppermill's Fireside Lounge (2985 S. Las Vegas Blvd.), which has a shag-carpeted fire pit. I repeat, it has a fire pit carpeted in shag. And plastic trees. Go at night for the full effect. Go to the lounge part, not the diner. Imagine "The Theme From Shaft" playing as you walk in. You have walked into a 70s time warp. Enjoy it while you're there.
Next time, try to time your visit for the annual Adult Entertainment Convention, so that you'll see all the porn stars and wannabes gambling in the casinos in the evening after sitting at the booths all day.