Right over a property a person included in in a Joint patta after the death of one person

After the death of my father in 1978, Revenue dept. of Tamil Nadu Govt included my name and my brother's name in the Patta for Dry land of nearly 6 acres. After 1980, my brother left out our family leaving our parents and sisters under my care and started wayward life at Chennai keeping many concubines. He never turned up to our native place and never cared about our parents, sisters and ancestral properties; all were left as barren lands without any cultivation as myself was in Govt employment at Chennai from 1971. Apart from my employment I took care of my sisters, mother in nourishing them giving treatment for heart ailment etc and maintained the lands. He never spent any paise for the cremations of my parents. In 2017 my brother suddenly went to my native place and stayed at my elder sister's house who was already married in 1969 itself leaving my family. and living with her husband. While staying at my sister's house, nearly a week he died on 10-4-2017 at her residence. On inquiry it was found that he left with no children but leaving a lady as his concubine. The dept has refused to issue a legal heir ship certificate in her favour. All the barren lands are in my possession from 1978 and paying land taxes etc. My brother never visited the lands and never asked for partition. All the properties were mortgaged by my father in 1968, 1969 to meet the expenses of my two sister’s marriages etc. Either my brother or my sisters never cared to release the mortgages and all of them were got cleared by me in 1989 from my own earnings. Therefore all are under my possession from 1980. Now as I am aged 75, I am afraid of my health and think that before my death, I want to sell 50% of the landed property of land standing in my name and the deceased brother in rev Records. But the Sub Registrar is refusing to register the sale deed saying that no partition was made earlier with my brother and insist production of partition deed. For the past 40years my brother never he never turned up to our native place and none of my relatives have seen him till his death.no chance of partition. All were under my possession and paying taxes by me for the entire properties. Getting a II nd class LHC for me will take several years and I may die leaving my children without any benefits. Before my death I want to sell 50% of my share. The lady who lived with him lastly has no evidence to prove that she is a legally wedded wife or not. 1) Is the Sub Registrar has right to refuse registration of sale deed to any person who is willing to purchase the land and 2) whether he has any power to dictate to me that eastern side. northern side south or northern side alone should be sold. Kindly clarify under what provision he can direct me or refuse. Kindly advise me the course of action to be taken to sell my share. Please sir