Hi
1) Since the properties are in the name of your mother and father, these properties are assumed to be self acquired properties of your mother and father.
2) These properties are not ancestral properties. So technically these properties will go in equal shares to you, your sister and brother.
3) If there were any ancestral properties and if any monies from these ancestral properties has been used to buy the properties in the name of your father then the property of your father will be ancestral property and you and your brother alone will be entitled to succeed to these properties as your sister will not be eligible to get a share of ancestral properties as she was married in the year 1983.
4) The court will look in to whether these are self acquired or ancestral properties. If these are self acquired properties, the properties will vest in equal shares amongst the children.
5) Properties standing in the name of mother will be her absolute property vide section 15 of Hindu succession act and hence these properties will be deemed self acquired property of the mother.
6) If the properties standing in name of the father are ancestral properties then they will vest with son's vide section 6 of Hindu succession act (as in your case the daughter was married prior to 1983). It is pertinent to note that even the Hindu succession act amendment brought by Shri. N.T.Rama Rao in the year 1986 granting daughter's equal rights as son in ancestral property will NOT be applicable in your case).
Hope this information is useful.