India

Yes you can explore about part time Ph.D. regulation in India. Universities like LPU, IGNOU Anamali offer Ph.D. with various option of attendance for working people. Specially LPU gives various type of Ph.D. attendance options.
Working people can opt for part time ph d fron institutions like IIFT, II

There may be minute difference in curriculum of different AIIMS. AIMS Rishikesh is one of the newly operation AIIMS in India thus may have less experience in medical teaching.
Curriculum of most of the AIMS is same .There is minute difference in teaching quality and practise and other rules .

To get into a college in Kerala you have to write the KEAM examination that is held every year.

Yes it is possible.

The main colleges that offer criminology are:
University of Kerala, Thiruvananthapuram
Sree Sankaracharya University of Sanskrit, Kalady
Kannur University, Kannur
Mahatma Gandhi University, Kottayam.

A few colleges for forensic Science near kottayam are:
Mahatma Gandhi University (government college), St. Berchmans College, Alphonsa College, Assumption College
Baselius College, Marian College,. .

A few colleges that offer B.Sc. In Astrophysics are :
University of Calicut, Malappuram
St. Thomas College, Thrissur
Sree Narayana College, Kollam
Sree Sankara College, Kalady
Nirmalagiri College, Kuthuparamba
St. Xavier's College for Women, Aluva
government. College, Chittur
St. Mary's College, Thrissur.

A few colleges that offer MCA course in Ernakulam are:
Rajagiri School of Engineering and Technology, FISAT Business School, St. Albert's College
Cochin University of Science and Technology (CUSAT), SCMS School of Technology and Management and Mar Athanasius College of Engineering.

You must have completed your Bachelor's degree in mathematics or Physics from a recognised university. You will be only able to get admission in good colleges for this course if you have higher % of marks in graduation. Separated entrance examinations are conducted by the different colleges for this