Since the property is registered on your mother in law name, it becomes her own and absolute property.

If at all any claim to be made about the ownership only your father in law should have taken steps to get the property declared on his name by filing a suit for declaration to declare title on his name on the basis of the funds he spent to purchase the property.

Now he is not living hence your mother in law title remains undisputed.

Therefore you cannot claim any share out of your mother in law property for any reason at least not during her lifetime.

The subsequent question is the repetition of the previous one.

But the answer is same that you are not entitled to any share in the property as a right even if the other siblings of your late husband are exparte.

It is your mother in law own and absolute property hence you cannot claim any rights in it at least not during her lifetime.

1) If your father-in-law bought it with his money and put it in his wife's name she is the owner  you will hace to price that father in law bought in wife nane fir benefit of joint family 

2) if your father-in-law inherited the money/property from his ancestors and then bought this house, your husband (and you) might have a coparcenary right.

3)file suit for partition for division of propery 

You will get share in property 

If the property, as per the title deeds, is in your mother in law's name, regardless of who paid for it, you cannot seek partition till she is alive. She has the right to bequeath it to anyone she likes. 

Your entitlement depends on who is the legal owner of the property, not on who paid the money.

If the property is registered in the name of your mother-in-law, then in law she is treated as the absolute owner, even if it was purchased from your father-in-law’s income. After the Benami Transactions (Prohibition) Act, 1988, you generally cannot claim that the property belongs to someone else merely because they paid for it.

Therefore, if the property is in your mother-in-law’s name:

• It is her self-acquired property
• Your deceased husband had no automatic share during her lifetime
• You cannot seek partition in that property while she is alive

A partition suit in such circumstances is likely to fail.

However, after your mother-in-law’s lifetime, if she dies without a Will, then the property will devolve under the Hindu Succession Act, 1956 to her legal heirs.

At that stage:

• Your husband’s share will pass to his legal heirs (which includes you and your children, if any)
• You can then claim through your husband’s share

Regarding your question about ex-parte proceedings:

Even if other parties do not appear and are set ex-parte, the court will still examine whether you have a legal right. If there is no legal entitlement, merely proceeding ex-parte will not guarantee a decree in your favour.

In summary:

• No right to partition during mother-in-law’s lifetime if property is in her name
• No claim based only on father-in-law’s income
• Right arises only after her death (if no Will)
• Ex-parte proceedings do not create rights where none exist

You need to file a suit showing that the said property is from the source income of father in law