Whether your mother is alive? If she is dead, is there a WILL? What about your father- is he alive or dead? Are there any other siblings to you apart from this brother?. If we can get answers to the above questions then it would be correct to give advice. Assuming you & your brother are the owners of the property, there would be no opposition from anybody in demolishing your house and rebuild the same by taking loan. Regarding sharing of 1 floor to your brother and retaining 2 floors to you can be done by mutual consensus. Please contact the municipal house to take permission to demolish the house and to take approval of the NEW BUILDING PLAN.