You do get basically the same benefits by breaking up your workout or doing more at a lower intensity. What matters isn't as much the intensity as the time versus intensity. Burning 500 calories in 45 minutes is basically the same as burning 500 calories in two hours.
The problem in this case isn't the actual time spent or his intensity... it's his ability to stick with it! Neither is helpful if he isn't doing it! Frankly, I find treadmill running insufferably boring; if that's all I had to do, I wouldn't do it, either!
Here's an article that can help break up the monotony: www.sparkpeople.com/resource/fitness_artic
Note that running whole-hog the entire time is a bit dangerous; you need to warm up and cool down properly or you're putting unnecessary strain on your body. If he can't workout for a week, he's definitely not doing it right!
Once a week is just not enough for really giving you any super great benefits. It's better than nothing, but science has shown that exercise for at least 30 minutes, 3 times per week provides GREAT heart-healthy benefits.