1) on father in law demise your husband , his brother , sister were legal heirs 

2)if your brother in law has taken over business and your husband relinquished his share as widow you would not have any share in the said business 

3). Check  with your sister in law whether they have relinquished their share in business 

you Can issue legal notice to brother in law to claim your share in family business on your husband demise 

2) brother in law in reply would mention your husband retirement from business or execute of relinquishment deed

you can claim same under domestic violence if the family business involved your husband share

You should file a maintenance application against your brother in law and mother in law. You are entitled to maintenance and they are obligated to pay you.

Yes you should file a maintenance application before the district court. The court shall order interim maintenance until the disposal of the case.

After your husband's demise without leaving a will, you, your mother in law, if alive and your daughter became legal heirs.

If your husband had relinquished his share, relinquishment deed needs mandatory registration, you can enquire from the sub registrar office in your jurisdiction whether any such deed was ever registered or not. If no relinquishment deed was registered, then you can claim your share in the property.

Even if the relinquishment deed was signed by her husband and registered, it can be challenged in court if it  was done under coercion, misrepresentation ,fraud or when he was suffering from any mental ailment.

You will have to do some enquiry first or you can simply ask your brother-in-law to show you the registered relinquishment deed or the same can be done by sending a legal notice too.

It appears your husband was a partner in the business 

After his demise the benefits of the business would survive to his legal heirs

The fact that you were being paid a monthly sum from out of the profits of that business, makes it somewhat appear that your husband was indeed a partner 

You also need to get hold of the document which was made to be signed by your husband and sister in law 

To lay a claim for a share in the business you will have to file a civil suit against your brother in law

Will is not required. If it was the sole proprietorship of your late father in law then on his demise the business devolved on his 2 sons equally and after demise of one of his sons, on the legal heirs of deceased son

1. The share of your father in law devolved through intestate succession on his widow and children.

2. On the demise of your husband his share in the share of his father devolved further on his mother, you and your children.

3. You may file a suit for partition in the competent civil court to cull out your share in the sale proceeds of the petrol pump and also seek permanent injunction against brother-in-law to restrain him from doing anything to stop you from taking part in the management of the petrol pump.

If it is a family business and devolved upon his legal heirs after the death of your father in law then you may claim a share out of your deceased husband's share in the business and property left behind by your father in law who is reported to have died intestate. 

First ascertain that if your deceased husband had relinquished his rights in the property and business by a registered release deed,  if not then you can ask for partition and separate possession of your deceased husband's share. 

If he's reluctant or refusing to come for any compromising arrangement then you may approach court seeking relief and remedy. 

Consult a local lawyer and discuss the subject matter at length to decide further course of legal action. 

See you need to check the business is in name of father in law or your brother in law i.e. the property is standing in who's name future the document signed is registered or not and what kind of document it is.

After that you can file a suit from side of you and your daughter feeling share  of your husband from the business.

See the pay cannot be secured if there is no agreement to that effect.

On father death , his share inherited in your husband and after his demise,  you and daughter inherited his share.

You can file partition suit. Signature on documents by your husband and sister will not affect your inheritance right until it is registered release deed.

Your husband is entitled to a share in your father in law's property who died intestate.

Like your mother in law and her other children, your husband is also one among the legal heirs of his deceased father.

Upon your husband's death, his share in that property shall again devolve on his own legal heir consisting his wife, children and his mother. 

you can claim your share through filing a partition suit. 

monthly payment is not secured but you can claim your share. 

Ans: Please inquire is whose name is that petrol pump registered??

If there was some agreement signed by your husband, get a copy of that agreement. as it will make things more clearer for your share in the agreement.

1. Yes you can file a suit for claiming your husband share from business as per partnership deed of petrol pump.

2. If they refuse to provide you the share then you can even file a suit on behalf of your daughter for claiming het rightful share in family business.