It is your brother self acquired property 

you or your children have no claim over the property 

The Property purchased by your brother by a registered sale deed on his name shall be his owen and absolute property.

In that property even his own children or wife or anyone can claim a share as a right.

If that is the case you are a third person to him, hence you cannot even think about getting any share in the property on his name by any means without any right or interests in it.

You should understand the law that the on class I legal heirs of your brother shall only be entitled to succeed to his properties if he is reported to have died intestate.

Your sons do not have any rights to claim a share in your own property during your lifetime, 

Your children do not have any rights or interests in your brother's properties either during his lifetime or after his death.

If your brother is bachelor on his demise you and your siblings would be legal heirs 

1. If the property is purchased out of the proceeds of sale any joint property. Even if a small portion is contributed, say 5%, from the sale of ancestral property, such property acquires the character of ancestral in which you will have share.
2. Any other family member contributed towards purchase of such property even 5% it becomes joint property.
3. If the property is purchased out to funds of family business it becomes joint property.
4. Apart from this there are some other circumstances under which property becomes joint family property in which  you will have right to share.
5. Under all above you can claim right with sons of brother. 

Dear Sir,

If it is self earned property, then until and unless your elder brother has specifically addressed in his will that you will be given a share, you are not entitled to property.

Thank you,

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Brother is class 2 legal heir. 

Since your brother brought property, after death of your brother you can claim if

-   There is no WILL

-   There are no class I legal heirs (his wife and children). 

So if there is no class I legal heirs then it will be divided equally to Class 2 legal heirs. 

Your sons claim is through you only. 

- if your brother is the owner of that property , then after his death his property would be devolved upon his legal heirs i.e. his wife and children. 

- Further, if he died without marriage , then his property can be claimed by your parents being the class I legal heir 

- Further, if no parents then only this property can be claimed by other legal heirs including you. 

1. Only and only if your elder brother dies intestate and issueless then his property will devolve through intestate succession on his siblings.

2. You have no right, title or interest in his property during his lifetime.

Dear Sir

If he is bachelor and dies without executing any document like Will etc.. then you will be entitled to get that property purchased by your brother.