hey 

Your son can definitely get into cse chennai branch under the first category.This im telling you based on the past record.Excellent scope during placements. 99% of the companies(core or IT) offer at least 3.25 lakhs to ECE undergrads. In my case only one company offered less than this. Core companies generally offer somewhere in the vicinity of 5–6 lakhs. Some might even offer 10+. And believe me you, there are quite a few(in 2014 we had Cadence, Cisco, McKinsey, Schlumberger, KLM Tencor, Future first, all offering salaries north of 10lakhs).

Then we have a few less paying firms like HP, Deloitte, Sapient, GM, GE and list goes on. All these pay above 5lpa but less than 8lpa. These are what placement cell classifies as the dream jobs. Get one and you lose your eligibility for the rest.And then there's mass recruitment, Accenture/Wipro/Infy etc. These also pay above 3lpa. But less than 4lpa.

So do try your luck here and all the best!

Regards