1. SINCE the Flat is in JOINT names, both brother have equal ownership rights and residing rights in the Flat. One single brother CANNOT ask the other brother to quit or vacate.
2. In your own interest, TILL you are in SOLE possession of the Flat, you are safe for your rights. The moment other brother occupies the Flat, you will be in great legal trouble, for your rights.
3. You do not allow him for anything inside the Flat and he will be forced to go to the Civil Court for relief, which will take years. ULTIMATELY he will come down for settlement, which will be just and good for both of you.
4. You CANNOT sell the Flat without his signature on the Sale Deed, even if you go the court and the Flat being a single unit, you cannot file any partition suit, for division of the property.
Keep Smiling .... Hemant Agarwal