Can nominee claim 50% in share in jointly owned property after one owner dies

I had purchased property in Mumbai in July 2005 with my source of funds. I have added my wife as a co-owner in the property and jointly signed the purchase deed with my name appearing first and her name second ( for example: Mr. A B C and Mrs.D A C) we also jointly nominated our son as 100% by filling out the form and submitted in the society. Now my wife passed away last month and my son has claimed 50% share as a nominee by writing the letter to society office to cease my rights by not allowing me to rent sell transfer the property. He also sent lawyer letter to the society office for ceasing my rights for not to rent sell transfer the property. I have purchased the property with absolute solo funds and paying all the society dues and property taxes from my individual bank account. Can I revoke the nominee from the property or m I the sole owner of the property in this situation? In our purchase agreement, percentage of share is not mentioned. Please give me your expert opinion. Thank you