With 89 percentile in JEE Mains and EWS category, your sister has a fair chance to get admission in some government colleges, especially newer or lower-ranked NITs and GFTIs. Top NITs may be difficult, but state engineering colleges and some good government-funded institutes accept EWS category students with this percentile.

She should participate in counseling, apply broadly, and check cutoff lists carefully. Also, keep improving her rank if possible for better options next time !