Also, I disagree with the fact that he'll be behind regarding career progression. Right now there is no movement. There will continue to be no movement for some time to come. Once movement begins (3-5 years), he can jump on and hang on for the ride and will have a quick thrust up the seniority lists.
You've got to have hours, I get it. But, even more than that is movement within the system. As any given particle in the stream of career progression in this industry, taking a job with Gojet vs. doing something else for a while likely will not make much of a difference down the road.
I work for TSA (not Gojet) myself and have decided to abandon ship in search of building other credentials during this downturn. If I come back to the industry, I have a hard time believing I'll be behind the power curve. Most of my contemporaries will likely still be struggling in the right seat for the next 2-3 years.