Advice for your friend
At 500TT, your friend ought to be teaching. Being an instructor isn't something a pilot does simply to book time. Being an instructor is something a pilot does to become a better pilot.
Every student is like a mirror held up that shows you your own flying skills. Their fears, hesitiations, mistakes and successes, are the very ones we all lived through when first learning to love flying. Helping students through each of these levels of experience makes the instructor a better pilot, and starts them on the way to becoming an aviator.
If your friend doesn't have 500 hours of dual given, he has a long way to go to be a capable and highly skilled instructor. It's a cliche, I know, but a very true one: Until you can teach a thing, you can't really do it. It's how physicians learn surgery!
I think that this is especially true in flying, where at the beginning (and trust me, 500TT is the BEGINNING), you are ever-so-capable of getting yourself and your passengers into situations you don't have the chops to fly out of.
I know that there are long arguments and threads on this board about this very thing. My own view, and my own experience as a pilot is, that at 500TT I imagined that I was a much better pilot than I now realize I was. I simply hadn't flown enough to have had the variety of experiences required to build the depth of judgement required to sit in the seat I so longed to occupy.
I think it is a personality trait amongst pilots to be impatient, to want to move ahead quickly to bigger and more powerful machinery that hurtles ever-faster through the sky. But we owe it to ourselves to take whatever time we need to build the portfolio of skills required to do this complex job.
500TT is an important milestone. I applaud your friend's dedication. But, sincerely, it's just the beginning. At 1500TT he's going to look back and realize he was the victim of arrogance that comes from inexperience. I was.
I hope he keeps plugging away and that he reads this thread. Some heavy hitters have weighed in with good advice. Following their advice has, in fact, been very helpful to the development of my own career (no brown-nosing here, it's just a fact of life on FlightInfo)