Hello

Yes,your sister have slight chances of getting admission in private medical college under government quota ,score 205 and sc category ;as last year cutoff for these colleges reached to 229 marks.

Also,there is increase in mbbs seats by 4,500 all over india ,so you can expect a medical seat .

Last year's cutoff marks for private medical colleges (government quota)in tamil nadu is mentioned in the given link below-

https://medicine.careers360.com/articles/neet-cutoff-tamil-nadu
I hope this information proves helpful to you.

All the best