CBSE 12th

Dear Abhishek,
Yes, you can easily get admission in Dehradun Institute of Technology because DIT fills some management seats directly. The procedure is simple, you will have to fill one admission form. DIT can charge the extra fee but you will easily get the admission.

To get good marks, you need to prepare well. Learn the concept and basics of mathematics, physics and chemistry. Practice numerical and derivation. Solve the last 10 years question papers. It will give you an idea how to tackle the questions in the exam. At last, stay positive & dedicate your quality time on self-study.
Best of luck.

You need to score a minimum of 65 percent marks in class 12th to pursue BCA.

There are chances for you. Best of luck!

You need to have a minimum of 60% in your UG. Thanks.

Both are very good in terms of cirriculum and knowledge offered.
In both, you will start studying from the basics which are taught in class 12th.
You can also do MBA after B.Com.
BBA+MBA is an another option.
All the best.

You have to have a minimum of 60% in your UG. Thanks.

Yes.
If your friend studies in CBSE class 11th in science then he/she can change the subject, but remember CBSE allows change of subjects only up to a limited time. For example, if one has non-med and wants to go to commerce or humanities then he/she should immediately submit the application to the Principal/Management.
I think school co-ordinators also alert you once in class 11th if someone wishes to change the subject. Otherwise, it will be too late for taking a decision.
Moreover, I don't think in class 12th CBSE allows subject change.
All the best.

Hello Sarika,
For his bright future allow him to follow his interests and let him explore his potential and abilities. Here are some options for a PCM student.
B.E./B.Tech
B.Sc
B.Arch
Defence
Navy
and so on.
If he has a keen interest in other subjects other than engineering then he can check B.Com, BBA, B.Sc-LLB, etc. Find out the psychometric tests online and ask him to take one to know his real aptitude.