Probate of will is mandatory requirement for purchasing a 25 year old

Dear experts, We are planning to buy a 25-year-old flat in Nanganallur. The owner had died last year and written a Will in 2011, given a Power of authority to her elder son the rights to sell the flat after her death, distribute the amount equal to the other 3 children after the sale, mentioned in the will. Now we have below queries 1. If we buy decide to proceed with buying of the flat, whether the will have to be mandatorily probated from the POA side in the Chennai High court, since Nanganallur (Part of Alandur- earlier come under Kancheepuram Jurisdiction), now became the part of Chennai corporation, post-2013 and provide us with the probate copy or Noc affidavit from all legal heirs side is fine to proceed. 2. Whether Nanganallur comes under the Chennai High court jurisdiction limit or part of Chelpet?