How can I claim a property right from my biological father who abandoned me?

Hello Lawyers, This could be a very complicated case, please bear with me. I come from Jhansi, in UP. My mother passed away while delivering me and my father decided to abandon me and got married to another lady. I was taken shelter by my aunt and uncle, whom I treat as my parents. They have not claimed to be my guardians; however, I have all my official documents in my biological father's name. I have been accepted into a foreign university in Germany for a master's program purely on merit. I wish to avail an education loan, but I do not have any financial resources. My foster parents are retired and my biological father is an auto-rickshaw driver, who does not want to give up his house for a mortgage. Recently I have found out that my biological great-grandfather has land in Jhansi, which my siblings have a share in. I wish to get my name attached/added to this plotted land, in order to get my education loan. Could you please guide me on the steps on how I can avail some part in this land? Also would a disputed land cause a rejection in my education loan? Do you have any help for me, in my case?