sonata32

This post is for my uncle's 2003 Elantra (50,000 miles). Last time he went
in for his oil change at Midas auto store, they checked his brakes and said
that he has 40% more wear until he would need new brakes. Well, he recently
noticed that his brake pedal has dropped significantly. When I drove the
car, I feel the brakes are ok as in the sense that they do stop the car and
there is no noise of rubbing or scraping. I am no mechanic but I do know
that the pedal is not where it is suppose to be. It almost touches the floor
when you apply the brakes. He is planning to bring his car in tomorrow at
Midas again for his oil change and have them recheck the brakes. Does anyone
have a clue as to might be the culprit. I been doing some research and I had
found that it can be a master cylinder problem (is this under warranty?) or
air in the brake lines. Who knows. I just am worried for him because he is
on a limited income (disabled and retired). Thanks group.