I guided Cayambe many (10-20?) times back in the mid-90s. This is normal for Cayambe. From the hut the route ascends a sandy/scree ridge to its end.
Basically you’re trying to get as much altitude as possible before you get onto the glacier which is quite active and ever-changing.
That said, I wonder if his guide had a clue as to where he was going because even 25 years ago there was a modicum of a trail. It was a PIA. And I do remember lots of clients turning around because of it. Also sounds like his guide didn’t pace him correctly.
Cototpaxi is usually a bit better for people because it’s only a touch higher, usually more straighforward (crevasse-glacier travel wise) and for whatever reason, it always seemed to have the best snow/ice conditions for cramponing.
Chimborazo also has a ton of crummy-volcanic scree hiking to get to the point where you can put on crampons.
Cayambe is also the most difficult for many because (since it is the lowest) it’s usually the first of 2-3 of these 18,000-20,000 foot peaks that are typically packed into a 2 week trip. Most of the canned commercial trips go something like: Hike to 14 from Quito, rest, drive to 14-ish, rest/skills day, climb cayambe, down/rest, climb cotopaxi, down/rest, drive to chimbo, climb chimbo. With the balance being slush days for weather, sickness, etc.
Hope that helps.