can i make a claim on my late mothers estate if if goes to the treasury she did not make a will.

could myself and my siblings lose our late mothers estate if it goes to the treasury?our brother says he paid the mortgage of said property(untrue) he cant prove this he's had 18mths but still wants half the property.refuses to reply to correspondence.our parents wanted it split 4 equal ways if anything happened to them,but our brother is contesting this but is doing nothing to solve it.we can not afford to go to court ,is there anything we can do? could we make a separate claim 4 it some other way,we don't want him 2 lose his share just to share it equal,He has done this before gone to court trying to get full custody of a property,and he was left paying costs.so this time he wont take it to court as he is waiting for us to do this.the property is being let monies going into the estate to