2) you can revoke POA given to sister if they are not willing to sell it to tenant 

2) inform your sisters that any buyer will not pay market price for property unless you deliver vacant possession and better to sell it to tenant 

1. Dispute is beyond argument, hence you are here.
2. First cancel POA/GPA. Once any transaction takes place through GPA, it is irreversible.
3. Though there is no preferential right in tenant to purchased tenanted property, as one of the co-owner of property is willing to sell the  property to tenant, other co-owners can be forced to sell the  property to tenant as held by Bombay High Court in 2021.
4. You can refuse to sell the property to others and hold up the  sale indefinitely forcing other legal heirs to come to your terms.

Since all 4 of you have got equal share , none of you unilaterally sell the whole property to a person of her/his choice.

Therefore, you can prevail upon your sister and if she does not agree then you can revoke your POA and refuse to sell your undivided 1/4th share in the property.

Additionally you can file a suit for partition and injunction. 

Since you have already given power of attorney deed to your sister you cannot do anything about it sitting in a foreign country.

you can request and convince her or you can revoke the power of attorney deed and make her to agree for compromised settlement because the tenant is protected by tenancy rights. 

You can sell the tenanted property can only if execute deed of assignment in favour of the buyer.

- As per law, after the demise of your father intestate, his said property would be devolved upon his all legal heirs equally. 

- Hence, your sister cannot sell the property without taking consent of all the legal heirs. 

- However, if you have given her POA dully attested from Canada then she has right to sell the same even on your behalf. 

- You can send a legal notice to her for the cancellation of the given POA and to stop doing any transaction related the properties. 

1. Legal Right to Sell: Since the property is jointly owned, all siblings must agree on the sale. Your sister cannot sell without your consent unless her POA explicitly grants her the right to sell on your behalf.

2. Tenant’s Legal Protection: Under Indian rent control laws, evicting a tenant is difficult, especially for long-term occupants. Selling to them is legally and practically safer than selling to an outsider who may later face legal challenges.

3. Ethical & Practical Argument:

   • Eviction of a protected tenant is a long and costly process, which may discourage any outsider from completing the purchase.
   • The tenant is offering nearly the same price, making the sale smoother and legally sound.
   • A new buyer may try to evict the tenant, leading to disputes and legal trouble.

4. Immediate Actions:

   • 
     Revoke the POA if it allows your sister to sell without your consent.
   • 
     Legally object to the sale by sending a written notice stating your disagreement.
   • 
     Engage a lawyer to ensure your rights as a co-owner are protected.
   • 
     Negotiate with your siblings and stress that selling to the tenant is the best option to avoid future disputes.

5. Final Steps: If your sister insists on selling, you can refuse to sign the sale deed or take legal action to prevent the sale. The property cannot be sold without all co-owners' consent.

For detailed, personalized advice, consider a phone consultancy. Hope you find the information helpful. You are free to contact me for further discussion. If you could spare two minutes of your time to write a review, it would be greatly appreciated and bring immense happiness to read it. Thank you. Shubham Goyal.