1. If your late father had signed an agreement for sale and the buyer had violated any of the terms mentioned in the said agreement, you can easily refuse to honour the said agreement for his non performance.
2. However, you shall have to refund him the amount taken by your father from him with applied rate of bank interest if the said biana amount is less than the value of the property which you have inherited from your late father.
3. In most of the agreement for sale it is written that in case the death of any party of the said agreement, his/her successor and heirs will abide by the terms mentioned in the instant agreement for which you will not be able to discard the agreement entered in to by your father after taking an amount towards biana on the sole ground that he is dead.
4. As regards his getting the biananama signed by your father improperly, you shall have to prove your allegation with evidence and in that case the said agreement will be treated as illegal hence void at law and even in that yoiu shall have to return him the money your later had taken from him towards biana..