I live in northern AZ, about 100 miles from Sedona, so I can't offer any specific builder recommendation, only some general observations.
Sedona, Prescott, Payson, Show Low and the smaller northern Arizona towns have experienced a building boom over the last couple of years. (Flagstaff is in a category by itself, IMO) Where I live, waiting lists for 'good' contractors is typically 12-18 months, and many require a large upfront amount to start and seem to take an inordinate amount of time to complete. There's been three custom homes completed in my subdivision over the last three years and min construction time is twelve months and the most is approaching four years (and the second builder) The resources to build are far outstripped by the demand, in general.
Of the towns I mentioned, Sedona is the most expensive and exclusive area. It has a world-wide recognition for beautiful red-rock scenery and woo-woo culture. In general, builders in northern AZ, and especially Sedona want to build the million dollar+ projects. "Modest home in Sedona" is practically an oxymoron. I'm not saying you're friend won't find a builder for a 'modest' project, but it will be an uphill battle.
I'd encourage your friend to vet any builders with the AZ Registrar of Contractors as there seems to be quite a bit of problems in this neck of the woods. A lot of social media sites have contractors and contractor complaint pages and it pays to look there too.
Sedona is close enough to Flagstaff that your friend might expand his contractor search to there too. IMO, Flagstaff housing is 20-30% more expensive than most places in northern AZ too, so get ready for some sticker shock
If your friend hasn't already purchased a property, I'd be looking in Verde Valley, Cottonwood, Prescott Valley area.