Hello,

As per the eligibility criteria specified by NTA for neet 2020, your sister is eligible to give the paper as her aggregate for PCB is 50 % and she has passed in all the three weather via grace or merit she has passed, so that makes her eligible to take the test.

You can Check out the other eligibility details and information from the link provided below:

https://medicine.careers360.com/articles/neet-eligibility-criteria

Hope this helps.