Well, he did it for himself! In his own home! He's not claiming to be a genius player! Come on, guys, you're annoying me :-)
You guys should be renamed to "stubborn" :-)
Okay, here's a little story with a kitten:
Who hasn't played GTA? Everyone (almost):) And many use cheats. But they don't play through the story; they just have fun and kill grandmothers in bathrooms. But if you play missions with cheats, it's just NOT interesting; there's no tension, no challenge. And even if the difficulty is too high, IMHO, it's better to struggle and figure it out yourself than to use a cheat:D
And all sorts of excuses like "I can't pass it" (this doesn't apply to anyone) are irrelevant; try, learn. Then you'll pass it, and you'll be so proud of yourself:)
P.S. Good luck in the argument:)