1) You cannot legally give up rights to property that you do not yet own.

2) The actual renunciation happens only after the inheritance occurs (after the death of the owner/parent).

3)  If the property is self-acquired by your parents, they can dispose of it as they wish, and you have no legal claim unless mentioned in a Will. If it is ancestral, you have a birthright, but it can be relinquished

Execute a registered Relinquishment Deed relinquishing your entire right over the parental  movable and immovable properties in the jurisdictional Sub Registrar's Office. 

You cannot technically "relinquish" a right that hasn't vested yet since they still own the property, hence you do not have any rights in the property which you propose to relinquish now. 

If the parents have  passed away and reported to have died intestate then you can execute a formal Relinquishment Deed or Release Deed relinquishing your legal rights in the property left behind by them. 

Therefore for now you can orally renounce and not relinquish though this renunciation has no legal effect in future and the same can be revoked. . 

You need to execute a registered relinquishment deed for the same

Your intention can be implemented, but it is important to understand one key legal position at the outset. In Indian law, a person cannot permanently waive or relinquish a future inheritance right before it actually accrues. Any such general declaration made today about “future inheritance” has only evidentiary value and is not fully binding in law. A legally enforceable relinquishment happens only after the property rights have crystallised, typically upon the death of the owner or once your share becomes identifiable.

If you still wish to formally record your intent, you can proceed in a structured and legally safer manner.

You may first execute a declaration or affidavit stating that you have no objection to your parents dealing with their property in any manner they deem fit, and that you do not intend to claim any right in such property in future. This document should be properly drafted, signed, notarised, and ideally registered to strengthen its evidentiary value. Copies can be shared with your parents, sibling and spouse for record.

If the property is self-acquired by your parents, the simplest and most effective way is for them to execute a Will clearly bequeathing the property to your brother or any other person. In such a case, your non-claim declaration will support the Will and reduce chances of dispute.

If the property is ancestral or joint family property, your share cannot be waived in advance through a simple declaration. In such cases, the legally recognised method is a registered release deed or family settlement, but this can only be done once your share is defined or has legally arisen.

A safer practical approach is to execute a “No Objection / No Claim Declaration” now, and if and when succession opens in future, execute a registered release deed in favour of the beneficiary at that stage. This two-step approach aligns with legal requirements and avoids future complications.

As a checklist, you should ensure that the declaration clearly identifies the property, records your voluntary intent without coercion, states that you will not raise claims, and is signed before witnesses and notarised or registered. Avoid signing any power of attorney unless absolutely necessary, as it creates separate legal authority.

In summary, you can certainly record your intent today, but a legally binding relinquishment will only take effect at the appropriate stage when rights actually accrue. If you want, I can help you draft a legally robust declaration tailored to your facts.

- You can execute a declaration after stating the said facts 

- Further, you can also publish a notice in the newspaper for debarring all the relation with them if you don't want to have any relation with them.