In general, first to qualify in NEET, a General Category candidate has to score 50% of the top NEET score. It is 40% for SC, ST, OBC. For example, if the top NEET scorer has scored 500, General Category candidates should score atleast 250 and SC,ST,OBC should score around 200 to qualify. Now not every qualified candidate can get a medical seat. It depends on cut offs. Now cut offs change every year and are dependant on various factors like no.of seats available, no.of candidates appearing for the exam, difficulty of the exam and top NEET score. Every State except Jammu and Kashmir has All India Quota and State Quota and there is different cut off for each quota. Now every State has various cut offs for every college and Category. Tamilnadu is one of the States with highest cut off. But States like Assam do not have that high cut off. So it totally depends on what State you want to apply and if you want to apply under All India Quota or State Quota. State Quota has higher cut off marks. For Tamilnadu, it should be atleast 625. But for Himachal Pradesh it is around 300. And you cannot be eligible for State Quota of every State which means you should also try for All India Quota. But without having an idea of which State you want to apply for, it is difficult to guess your chances. For example, with the cut offs that Tamilnadu has, one can easily get a seat in a Govt. Medical college in West Bengal.

You have good chances as per the status also the 583 is an awesome score to get a government collage seet

All the best

Refer this link for rank presicpred

Https://medicine.careers360.com/articles/neet-college-predictor

Hiiiii I Mr. Rajesh!!!! Congratulations first of all. Your son has a good chance of getting into a government medical college because last year the cut off marks had started from around 450 marks for BC-B category. Although the cut off varies a bit, it will be around these marks only.