Hello aspirant!!

Sorry for your sister's JEE rank the chances of getting good Universities are nearly null. But try to apply for private colleges which accepts JEE Mains rank and gives seat under B Category so that you can ensure a seat. 

Go through the below mentioned link to know which colleges you get for your rank. 

https://engineering.careers360.com/jee-main-college-predictor

Hope this helps you :)

Good Luck!!

Thank you.