Vellore Institute of Technology - Chennai Campus

Then he can wait till the next round of the counselling and in the next round of the counselling, your son can go and attend that, only then he is able to get admission in this college.

You cannot get the main campus at this rank and getting the CSE branch at this rank is not even possible in any of the campus. You apply for the management quota, then you can get the main campus.

No, there is no chances of getting admission in any of the campus of the VIT. With this rank, you can get admission in AP campus only through the management quota.

Vit is a good university and has high credentials. It has got a good name and prestige. The market must have a good value of the same and also you should be getting a good placement with the vit tag on your degrees

According to your rank, you will easily get VIT-Vellore in the 2nd or maximum in the 3rd round. Suppose, if 1% you didn't get Vellore then you will get Chennai easily, but I would suggest you be focused on Vellore and don't try to go with Chennai campus of VIT.

If you are in the final year of your degree then you can give placement tests. But if you are pass out then you can not do this. Good luck.

Yes you can get admission in Vellore or Chennai. But, you won't get CSE in Vellore, and if you do get it in Chennai, it will in category 4 mostly. You can get courses in Chennai campus like EEE, ECM or Civil.

Vellore and Chennai have common placements.
Placement record is good, almost everyone gets placed. There are people who go at 18L per annum also. You can find a lot of people going at 8-15L as well. Most people get placed in the 5-8L bracket. Mass recruiters pay less and people joining those get around 3-4L per annum.
We have big 4 that come every year.
Companies like GE, Suzuki, Cisco, TI, NI, Intel, Microsoft are a few I can remember as of now.
IT companies like Wipro, Cognizant and Infosys come to campus.

So I believe in terms of education both VIT Chennai and Vellore impart the same. However, Chennai has a better student to faculty ratio and so you would have more opportunities to do something rather than just get lost in the crowd. Placements are joint so that won't be an issue. Generally when people decide between Vellore and Chennai with a branch like ECE it comes down to:
Vellore is a bigger campus and has grander fests. Chennai is a metro city and has better facilities. Rest assured the VIT Brand name will be evident in both the campus.