As per your query let me tell you,. that in order to enrol as an advocate an individual must have a bachelor degree in law (with minimum 50% in graduation), and such a degree should have been obtained from a college/university which has been recognised by the Bar Council of India.
However, the BCI states that a person shall not be allowed to practice as an advocate if either:- 1.) He/she is below 21 years of age, or 2.) He/she is 45 years or more by the time of enrolment with the State Bar Council (SBC).
After the above-mentioned points the one and only important aspect of being an advocate is requires graduation in law as a major criteria. Thus, if you're friend does not fall under the above-mentioned classification, then he is free to enroll himself as an advocate in any place across India, without any problem regardless of the fact that he's pursuing LL.M