India Eligibility

PCB main subject & must passed 12th or pursuing 12th with minimum 75% in intermediate exams.

There is no fee concession. But they will provide scholarships.

I am not 100% sure but foreign universities doesn't consider BCA as an engineering course. I believe only B.Tech students can only pursue their MS in Computers from the US. BCA holds less value in the US. Although, you should consider talking with that university to clear the doubts.

You might not be able to get admission into Techno India but still there are numerous universities and colleges which will get you admission into BCA. So, don't worry you can still pursue BCA course. If you want to learn programming languages which you will be studying in your BCA course then you can check out this app which is specially designed and developed for BCA students. It has programs and assignments of languages like C, C+ and Java with their outputs. You'll be studying these languages in your 3 years of BCA. https://play.google.com/store/apps/details?id=technark.bca_courprogramming.

Sharing a link with you, you can use the below link and predict the college and the stream:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

The criteria differ from one college to another. Yet, this is the common eligibility criteria:
Candidates must have passed the qualifying examination I. e. senior secondary or any other examination equivalent to 12 years of schooling in India. Must have minimum aggregate marks of 60% or 6.75 CGPA on 10 point Scale or Equivalent Grades in all the subject of the qualifying examination.

Domicile certificate maybe required in most institution. Educational purpose certificates are easier to get and requires less years and documentation. An aadhaar card always helps and voter card, land/property tax receipt exceeds the requirement.

Hi Syed!
It doesn't matter from where your son has completed his intermediate. The only thing which is important is that he needs to clear all subjects. Yes he is eligible to apply under DASA.
Don't worry.
Best of luck.