Distribution Of Property Among Legal Heirs

My Dad died Intestate leaving behind his widow and 2 sons (including me) and a daughter. My mother is aged 90 and is suffering from Alzheimer. Soon after my Dad's death the legal heirs entered into a FSA agreeing to distribute the father's estate only after mother's demise. Now my bro and sis are insisting on distributing the moveable portions of the property and keeping intact the immovable part consisting of a house occupied by Mom & younger bro. My question is whether the Succession Act provide for such piecemeal distribution i e not distributing the immovable along with the moveable portion. Suppose one of the legal heirs does not give his consent on such distribution then what is the remedy available to others. As Mom is not capable of entering into contracts how can her interest and future caretaking be safeguarded?