Qtv Telugu 14 May 2022
G.L.N. Prasad (Retired employee.) 15 May 2022
Contact someone in the UK (you can explore face book or your friends' links) and get facts first. As of now, there is no case against him and the status is not known to you. Your sister can write a petition or seek information through the online RTI India portal with Rs.10/- fee from the Indian embassy and can seek such information under the "Life or Liberty clause:
Kishor Mehta (CEO) 15 May 2022
Write to Indian Embassy in U.K. with his full details, if he has married in U.K. the details will be easy to acquire. It is more difficult and nearly impossible to find his marriage details in India. However it will a sfe bet for you to file divorce proceedings in India. You do not have a legal right to ask for the cancellation of his passport unless you can prove beyond all reasonable doubts about his act of bigamy.
Dr J C Vashista (Advocate) 16 May 2022
Your query
"How find where he got married (indian or uk)
How to find marriage proof from embassy."
None of the above questions are legal disputes for consideration and obligation of experts on this platform.