TRUE OR FALSE?

I don't think that anyone can properly answer your question here without more information about the program to which you're applying. Different schools use GMAT scores in different ways; for some, the Quant section is especially important, while for others, it's the score out of 800 which matters most.

If you do genuinely need a 550 for your application, then you can't ignore the Verbal section. The Quant and the Verbal sections make an equal contribution to your score out of 800, and if you were to completely tank the Verbal, you wouldn't have much of a chance to get a score over 550. That said, the Verbal section is less knowledge-based than the Quant, so it is more difficult to improve at Verbal than it is at Quant. That might be the reason your adviser suggested you focus on Quant. I would not recommend you ignore the Verbal completely - you should become familiar with the question types, and you can certainly significantly improve at Sentence Correction with study if that's a weak area - but you should probably plan to spend the majority of your study time on math.

There is a third component of the test, the AWA section (the essays). Many schools ignore these completely, and your score on the essays is unlikely to be important. Be sure to do the essays on test day, since a 0 in that section does not look good on an application, but you would not want to spend much time preparing for them.