Class 12-science

You need to first complete your graduation to be eligible for banking sector.

Hi Ashutosh,
Some popular exams are:
JEE Mains
JEE Advanced
BITSAT
NATA (National Aptitude Test in Architecture)
VITEEE
AIIMS-MBBS
National Defence Academy (NDA) and Naval Academy (NA) Exams

To study in the US you need to do the following: Score very well in academics at school. Register for SAT or ACT. Register for TOEFL iBT, Start researching about the Universities you want to go to. Start working on the university Application via CommonApp. You can also apply to Scholarships like Next Genius Scholarship Program or Tata Scholarship.

Kindly refer to the link mentioned below B.Tech in mechanical engineering colleges:
https://engineering.shiksha.com/be-btech-in-mechanical-engineering-courses-in-mumbai-all-ctpg

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.

It is always advisable to stick to your field. But, as a change for UG with a science background, I would suggest you to pursue BCA and MCA. Otherwise, you can go for B.Com.
All the best.

I would suggest you to go for B.Tech CSE or IT. You can go for it, if you have interest in computer science.