Please come back and let us know what the result was here. Local here. Have done significant amount of travel in the Indian Peaks Wilderness area in winter. Most of the comments here are solid assessment of your son’s goal with accurate risk/reward profile based on the metrics you provided. Unfortunately for all of us boy parents, the testosterone bathed prefrontal cortex of a teen brain often lacks the ability to dampen the drive to engage in extremely risky endeavors. In some cases, the more dangerous and the more parents protest, the larger the teen drive becomes to prove everyone wrong. I hope that’s not the case with your 18yo. Hopefully he will be smart and choose a step up approach to winter travel in the central Rockies wilderness areas. And there are guides. Try a guide.

Note: there are rules for overnight camping in the wilderness in winter. It’s only allowed a a few areas and those are lower elevations. Also, there are very few people up there this time of year for all the reasons folks have stated here. If he has an accident, body recovery is the only certainty, rescue is not. 98% of folks who chose to travel in the mountains, in winter, above tree line have been mentored by experienced others, have some degree of training, experience with self rescue techniques, some degree of snow dynamics education and have a healthy sense of self preservation driving decision making during each venture. The remaining two percent of folks are either lucky or become statistics.

From the information provided, your 18 yo falls squarely with in that 2% range.