My impression is that the crowd at Del Lago are mostly adults, but it's not Leisure World. The complex across the street are just apartments (or condos), not "assisted living", or a nursing home. Some people are there with their school-age kids, but I think most are 50-something -- adult, with grown-up kids so they don't have to stay at home every night anymore.
When I saw Roland and Etienne lately, they were doing a lot more pop stuff (versus the All Torch Song set I'd heard before). The ones I remember are "Twist and Shout", "I've Just Seen a Face" (!), and a cheesy "You've Got a Friend / Somebody To Lean On" medley. Etienne introduced a very large Latino woman who sang a Mexican love (?) song along with Roland on classical guitar, and then a quite passable "Crazy" with Roland back on "honky-tonk" piano. (I'm beginning to think that Roland is a Really Good piano player, and very versatile. Etienne, on the other hand, is way too cheesy for me -- she thinks she's on Broadway, and it's a little much.)
I think the clientele is up for the middle-years songs we have going -- Beatles and James. Even my mom, at 70, is a big James Taylor fan -- she's not looking to hear "Someone To Watch Over Me" all the time. I didn't really learn those songs to have some age-matched songs for people of that bracket -- I learned 'em like Willie and Linda Ronstadt did, 'cuz they're classics, and fun to re-interpret. I would never learn 'em on cheesy jazz piano and try to do/be (no pun intended) Sinatra with 'em. (And, yes, I know that if I'm not *in* the cheese, I can reach out and touch it with "Crying", and some others, but sometimes you just gotta push that edge.)
Anyway, I think it'll be a lot easier to pass our late-60s-to-70s-heavy song list off on 50-somethings than on the 20-somethings we'd be getting at Diedrich.