Hello, hope you are doing well.

Yes your friend suffering from bilateral subcapsular cataract falls under the category of physically challenged students.

She is eligible to write the NEET 2021 exam if her eyesight is 40% less in visibility than the normal eye's visibility. Ask her to get her eyesight checked and also you should check all the guidelines for handicapped students for NEET 2021 in detail.

Hope this solves your query.

Have a nice day.