It's illegal and very unresponsible.
I will disagree. 7.5 miles in the desert with no water or survival gear is no easy task.
He thought through the problem, analyzed it to the best of his ability and made a decision. There was no damage to the aircraft and all turned out well.
What was irresponsible, (and you can guarantee he will never do it again---therefore chalk it up to a learning experience), is flying over unforgiving terrain with no survival pack and/or water.
Also he will learn to NOT plug in ANY electronics until the alternator/generator is up and running......do your planning in the hotel at night.