JOINT HOME LOAN BENEFIT UNDER INCOME TAX

Respected Sir, Good Morning Sir, I have taken Home Loan(Joint) for Rs. 15 lacs with my brother for construction of House. Details of Loan                        Rs. 15 lacs Plot                                         300 Sq ft( 50% share of each mentioned in Registry means 150 sq ft each) Construction                           Construction  competed in Apr 16 (under 3 years from the loan taken) EMI                                         Both pay EMI i.e 50% of the total amount. Employment                            Both are Govt employee Sir now please clarify the below:- (a) Can we take both benefit of Income Tax i.e on principal and interest (b) what documents reqd to be given to my employer to take benefit of income tax (c) I request to my employer to give me benefit of 50% on Principal and Interest and enclosed Provisional Interest Certificate. But, My official said that it is not mentioned in the loan that you are both paying 50%  of the Home Loan.   As I shown in my property return liability of Rs.7.50 lacs (50% of the loan) They said you filled a affidavit for home loan to share the each of the individual and both are being claimed  50% on principal and interest . is it correct to filled a affidavit for the same. (d) MOST IMPORTANT -  If I not claimed benefit under Income Tax from my employer.  Can I claimed later on while filling the Income Tax Return and claimed refund.  is this correct or not. Kindly brief if any difficulty/implications in this regard. Thanking you Sir, Kamal