Claim of Property registered in my mother's name

My father's brother's family lives with us in the same property and the property is registered in my mother's name .My uncle's family has been living with us for last 20 years but they work separately . We don't have any ancestral property and whatever we have was earned by my father .My Uncle's family is not paying anything like rent or property tax or electricity bill from the beginning and now they are harassing my parents for transfer of half the property . My Parents live alone and they regularly threaten my parents with consequences if the half portion is not transferred in their name . I live in another town and I am regularly worried. Please advise whether they have any claim on my mother's property even though they have been living there for a long time .