1) since land and house is in your father name your father would be eligible to take loan against property .
2) you can be a co applicant of loan since your father may not be granted loan if he is a senior citizen
3) your father can also execute sale / gift deed in your favour for 50% share in the house
4) if you are then reconstructing the house and paying EMI then you would be eligible to claim tax benefits for loan repaid by you