Assuming last yr's scenario you try for IIT Palakkad and IIT Tirupathi Civil Eng. I dont know much about IIT Dhanbad but do try for the above mentioned colleges rather than opting for NITs. Obviously the tag 'IIT' is greater than 'NIT'.

According to last year marks bs rank criteria with 175 marks in the JEE Advanced examination under the general category tab you son can get a rank around 10,000 So getting into NITs is a bteer option and for IITs newer IITs can get a chance into Metallurgy branch 

Virendra according to last year marks bs rank criteria with 175 marks in the JEE Advanced examination under the general category tab you son can get a rank around 10,800. Although according to experts as the difficulty of paper in this exam was more in comparison to the last year so it is expected that cut-off will be lower which means that your son can get a little better rank with the same marks. you can expect the rank to be in the range of 9000-10,000. Although as rank is a totally relative phenomenon so it is very hard to get an accurate rank range with the marks. 

With this rank, it will be quite difficult for your son to get into the older IITs for any stream but there is a slim chance to get admission in newer IITs. You can check out the last-year cut-offs of different branches of different IITs by going through the link mentioned below:

• https://engineering.careers360.com/articles/jee-advanced-cutoff-for-iits

Feel free to ask if you have any more queries. All the best!!