You should buy property only in your name 

2) the reason being if you buy it in mother name on her demise intestate your siblings can claim equal share in property 

You should buy it in your name. You are not taxed if you buy a property. Capital gains tax is applicable when you sell it. Therefore if you buy the land and construct a house it would not be taxable.

Income tax is only applicable if you derive any income from it.

It is always advisable that you purchase the house property on your name (if possible you can include your spouse as a joint owner) and can make your parents to stay  and reside in that house property till their lifetime or until they would like to reside there.

In such a situation nobody can claim any rights over this property for any reason in future including your brother who appears not to be in good relationship with you.

There is no restrictions for a foreign citizen having OCI card  to purchase a residential property

You can buy the same as aforesaid

The applicable taxes will need to be paid

As an NRI, you are entitled to buy a residential property in India in your own name. If it is meant for your parents' living there, the question of rental income does not arise. You may execute a special PoA in your sister's name to purchase the property in India. 

Dear Client,

As per the facts which have been provided, you should buy the property in your name.

Thank You.

Yes she can make will and you can inherit the same from it

Mother can execute registered will bequeathing property to you 

mention reasons why she is not giving share to your siblings 

on sale of property it would attract capital gains tax 

The idea of transferring the property subsequently in your favor by a testamentary disposition i.e., by a Will is alright but the hidden danger in it is that you have to obtain No objection certificate from other legal heirs at the time of enforcing the Will i.e., at the time of acquisition of the property.

If the other legal heirs are objecting or demanding any share in the property then you may have to drag them to court of law seeking justice which will stretch to few years in the form of litigation.

Besides there is another danger that the Testator i.e., your mother who will be writing the Will bequeathing the property may change the Will or cancel it any time before her lifetime which  may bot even come to your knowledge.

Therefore you can think about all these aspects before hurrying to invest into this property.

You can think about all aspects before taking a decision in haste. 

- As per law, even being OCI , you can purchase residential or commercial property in India without taking permission from RBI. 

- If you will purchase in the name of your parents , then there may be trouble for claiming the property , and hence you should purchase in your name . 

- Further , if you will purchase the property in your parents name , then they can gift you for saving the tax implication , however registration after paying the stamp duty is mandatory . 

- Further, if your parents will write a WILL , then it will execute only after his demise , and then other legal heirs may create trouble for you. 

Dear Client,

As per the facts which have been provided, mother can execute a will and you can inherit the property.

Thank You.