What is the ruling of Islamic law regarding the purchase of an apartment seized illegally by a lawyer, in order to resolve a dispute, knowing that its price was paid by one of the heirs for all heirs to own it? Should it be divided among them and its cost borne by them, or should it be considered for the sole purchaser since it was registered in his name?

There is no objection to the heirs agreeing to purchase the apartment and dividing its price equally among themselves, or according to their inheritance shares, where each heir pays their portion of the price. You can request that the apartment, along with its ground floor, be specifically yours with their consent. Reconciliation is advised to preserve brotherhood and kinship ties.