well it's possible for steroids to help him loose fat indirectly, but i don't think it's realistic to think this effect would be particularly pronounced. what i'm referring to is how the more muscle he packs on the more calories he'll be burning around the clock.
nevertheless he's taking a (imo) serious health risk compounding pre-existing blood pressure and cholesterol issues like gym**rat says.
a better approach would be to first loose all the weight you can with proper diet and exercise prior to hormone administration gh15 style. i frown on people who think steroids are the magic bullet. no, regardless of what you're "on" it takes hard work to have an impressive physic.