Hello Aman,

As per the Official Brochure, Benefit would be given to those who have at least 40% impairment irrespective of the type of disability i.e., locomotor, visual or SEVERE dyslexic.

The Documents you require: 

Physical Disability certificate (FORM-PwD II/III/IV whichever is applicable]) issued by the notified medical authority.

Dyslexic candidate needs to submit FORM-DYSLEXIC 1 and 2 instead of FORM-PwD. The certificate must mention ‘SEVERE’ to enable the candidate get the benefit of PwD category.

Individual IITs may constitute a medical board at the time of admission to test the candidate’s level of disability.

You can refer the below given link to check the other information

JEE Advance 2019

Good Luck!