Mero sathiko gpa pugena re for grad school so he wants to go back to undergrad and study a different major. So what we are concerned about is that does the gpa add up if he does under grad again in different major at same/ different school.
His plan to do undergrad again is to improve his gpa to 3.5.

Thanx for the help.

Is he doing the whole 4 years again? If not, Is the new school transferring his credits?
Many grad school applications require you to submit all the transcripts and grades for schools attended, your( ok his) gpa from old school thus need to be listed.

Don't have to do a whole new major. Just retake the classes that got messed up and then pull up your gpa.

 If he is going to school for the different major then he has to finish all the course requirement. This might take minimum of 3 years (in case he does not have to take general education classes). Spending 3 more years for getting a good gpa does not seem a good idea to me. 
Let's say he wants to do minor in some related major. I am not sure but my believe there is different minor gpa which also does not add up to the major gpa.

Most of the grad schools requires minimum gpa of 3 to apply. If his gpa is beliw 3 and wants to get gpa of 3.5 taking the classes again or taking a different major does not seem possible. GPA ma k huncha bhane, classes lidai jada total credit ni badhdai jancha. cgpa sadhai total class credit le divide huncha tesaile class ma 'A' leraye ni total cgpa khassai increase hudaina.