1. in the present situation a suit for eviction is the legal option, which will take few years to end this dispute. For this first send a legal notice demanding to vacate the premise of 250 sqft as per the settlement deed. if not responded positively file an eviction suit
3. who are these relatives, Are they legal heirs to B. since both the parties A & B, mentioned are brothers, and the party "A " was unmarried, if he died intestate, "B" automatically is one of the legal heir of "A" and have right to his rest of the share.
2. Before initiating the eviction proceedings in the court, it is better to see whether you can call them for a discussion and reach to a settlement.
3. If the relatives are not ready to hand over the possession, you have no other option than approaching a court with an eviction suit.