Legal Question in Real Estate Law in New York

If your mom is the owner of the house ( her name is on the deed) and you and your sisters are not , there are very few things you can do. You can file a lawsuit against her, and attempt to get the house from her through the intervention of the court. But if you want to stop the sale, you need to file an order to show cause, with temporary injunction, stopping the sale until the court can hear you case.

Everything depends on how the deed reads. Either you have no case (deed reads Father + Mother) or you have a slam dunk (Father alone on deed and no will).

Facts are missing, as shown by other comments. Who was the owner of the property when Dad was living. Dad aone, or Dad and Mom? If both were on the Deed, and ownership was not shown as tenants in common, Mom probably became the rightful owner on Dad's death and she can do whatever she wants now, as none of the children have an interest in the house. Mom does not need your permission to sell it and does not have to give you a first right to buy it. It sounds like the relations between the children and Mom are strained, as it seems that as long as you are offering the same money she could get from someone else, and she refuses to sell to you, the relationship is damaged. Your sister may have a claim to be reimbursed for the money she spent. More facts are needed to discuss this issue also.