NIOS 12th

Before you begin, you must ensure you have passed class 12 with at least 55% in maths and physics individually. This is mandatory. You need to visit the websites of different flying schools in India and apply for a seat. A few of them will organise an entrance test where you will face a written round, an interview and the notorious pilot aptitude test. It will be a good idea to apply in as many flight schools as possible, provided their entrance exam schedules don't clash. You must be prepared for science and maths related question from class 9 to 12, NCERT syllabus. Do brush-up your skills in english too. The pilot aptitude test will test your hand-eye coordination and multitasking skills, your need to have a flexible mind to make it in. Flight schools don't just take in people with no knowledge about aviation, so do some research on planes, air crashes and basics of flight.
About the licences, you can refer https://ask.shiksha.com/what-is-the-difference-between-a-cpl-spl-or-ppl-at-what-point-does-one-go-for-these-qna-4368686

Yes, you can do MBBS abroad. From year 2017 Medical Council of India (MCI) has stopped issuing Eligibility Certificates to candidates who are taking MBBS admission abroad on the basis of National Institute of Open Schooling (NIOS) Certificates and Mark sheets and even State Open Schools. This means Foreign Medical Graduate degree of these students will not be valid in India and hence they can not appear for MCI Screening Test, which is mandatory to clear to be eligible to practice in India. However, your degree will be valid in the country abroad from where you decide to study and a candidate can practice there after obtaining the necessary license to practice as a Doctor in that country. Hope this helps you. Be free to share any problem you have. All the best for your bright future!