Vijay,

Almost around 10,000-12,000 PWD students appear every year in JEE mains. And everyone among them qualifies to give JEE advance as there is a total of 12,500 qualification slots for them. Now considering last year in percentile system the cutoff was around 0.011 percentile. Which is almost the very last rank. When marks were being counted the cutoff was -35 for PWD candidates. So, just giving the JEE main exam qualifies you to give the advance exam.

And even this year the number won't vary by much and lie around 10 thousand.

Hope this helps you!