Transfer of part of property to one brother to another

I along with my brother booked one flat from the builder in 2012 value of rs 51 lakh with equal shares (50%) . This flat have loan from SBI of rs 40.8 Lakhs. Possession given in 2016 March after the registry. loan is being paid since June 2012 in equal installement of Rs 21392/- from each account. As my brother is having financial problem since 2013 so I also used to pay his instalment by transferring the amount to his account. Since July 2016 I am paying the total EMI from my own single account. Brother want to sell his rights to me and a mutual amount of rs 13.8 Lakhs has been decided. How to go about this. I want to ensure the following 1. Agreement for relinquishment of rights over the property from buyer to seller. Remember property is presently mortgaged with SBI. 2. Securing the Rights of buyer as he need to have full rights from seller of his part by making payment . 3. Payment of stamp duty to the government on the total proceed. 4. Ensuring no further claim from seller or his family on the property in future. 5. Responsibility of payment of Loan lies with the Buyer and he agree. 6. How to proceed and sample format of deed covering all the points.