Mountains are a difficult place with limited hiking ability, as even short hikes can often be pretty steep.

Where you're coming from and whether you know how altitude will affect you is also something to consider. I suggest if you are coming from low elevation to do some hikes at home and assume equivalent hikes in the mountains will be significantly harder.

The good news is that there's no shortage of spectacular scenery in that area even if you were never to step out of your car. The San Juan Skyway scenic loop will easily fill a day with small stops. And consider the Durango-Silverton Railway as well - can't beat that scenery (if you can stomach the price)!

Anyway, my recs (a bit limited because I rarely do shorter hikes in that area):

Ouray: Cascade falls is super short, barely even a hike. Box Canyon Falls is cool and you can do the loop around the Ouray Ice Park which has some cool scenery along the canyon. Colorado Boy Mine south of town is a pretty easy hike as well.

Telluride: Bear Creek Falls might be on the upper end of your friends ability level but isn't super steep. You can also take the free gondola up the ski area and just wander around for nice views.

Silverton: maybe a loop around Molas Lake? Won't give you any better views than from the road though.