How should we try to sell this house?

[Kristi C.]

My mother and my uncle co-own a house that belonged to my grandmother. My uncle is a very unreasonable and unpleasant person with mental problems, anger issues, and violent tendencies. Just believe me when I say it's not possible to talk to him about the house, AT ALL. 

My mother would like to sell it. She has been paying property tax and lawn care on the house. Uncle refuses to pay anything for its taxes or lawn maintenance. 

What would be the best way to force the sale of this property? I would love to buy the house. It is impossible to just buy it directly because of my uncle's refusal to speak.