What are demands of your brother 

you can collect your share of compensation amount from the authorities by accepting the compensation awarded 

Approach the concerned Government Official and apprise him to consider you and your brother's willingness to receive the compensation amount, inspite of your another brother not ready to sign the papers.

Yes you can go to the authorities and seek assistance. You can clarify the situation and demand your share.

You can leave the brother alone to settle his problem by himself while you can collect your share in it individually.

If your brother is refusing to cooperate with you on this, then you can decide to ignore him and claim your share of consideration amount alone.

You can approach court under Specific relief act if he has agreed earlier 

Dear client,  

If all three brothers are named as claimants in the compensation awarded by the government, then all three brothers will have to sign the necessary documents to receive the compensation amount. If one brother refuses to sign, it can create a legal hurdle to receive the full compensation amount.

However, if the compensation amount has already been disbursed to a joint account held by all three brothers, then it may be possible for the other two brothers to withdraw their share of the compensation from the joint account, provided there is no legal injunction preventing them from doing so.

It's recommended to consult with a local lawyer who can review the specific circumstances of your case and provide you with guidance on the legal options available to you. The lawyer can also help you negotiate with the brother who is refusing to sign and try to reach a mutually acceptable solution.

File suit in court for direction to authorities to release your share