If you and your sibling have rights and a legitimate share in the property left behind by your deceased father who is reported to have died intestate, then this will be considered as intestate succession as per Indian Succession act.
Under this law, you and your sibling, if want to relinquish your rights i the property, you both can either execute a registered release deed jointly or separately in your mother's favor.
If you are residing in abroad, you may execute a power of attorney deed from that country itself duly attested by a notary or an Indian embassy higher officer of that country, send it to India to the person who you appoint as your lawful attorney, he would execute the registered release deed on your behalf in your mother's favor.
Once the release deed is executed in your mother's favor, she will become the absolute owner of the property with marketable title.
After that she can transfer the property to anyone of her choice in any manner as prescribed in law, at her will.