Your mother can apply for legal heir certificate

2) the name of class I legal heirs should be mentioned in legal heir certificate

3) your mother cannot arbitrarily exclude some legal heirs

After the demise of your father as per Hindu succession act your mother and your siblings are legal heirs .Any of the member can file application for getting legal heirship certificate .

A succession certificate is issued by a civil court to the legal heirs of a deceased person. If a person dies without leaving a will, a succession certificate can be granted by the court to realise the debts and securities of the deceased.

The legal heirs of your father are his widow and children. The share of your brother who died has devolved further on his legal heirs i.e widow and children. All the legal heirs should apply for a legal heir certificate.

1. The legal heirs would be all his children . If any of them then their children would be named in the certificate.

2. In Tehsildar's office such certificate is issued.

3. if not then you can apply for succession certificate from court.

according to Hindu personal law, a widow (your mother) has limited interest in her husband's property. children of deceased father are the legal heir and they are called heir of 1st tier. in absence of children his widow has right over the property.

you should prepare family register or succession certificate in the name of children (your siblings) and mother. absolute right will vest in children and a portion of , limited right , vest in your mother.

your elder brother has died so his children has accrued right to acquire his father's share in the property.

For getting the properties of your father who is reported to have died intestate, you can obtain legal heirship certificate.

The legal heirs shall be your mother, yourself, your sister, the legal heirs of your deceased brother.

However it may be too late for obtaining legal heirship certificate of a person who has died in the 1987, but you may approach the revenue department for this.