After inheritance you and your brother are not co-owner. 

So there is no problem in selling your share in the property to any outsider

Sell your share by excuting a sale deed. 

1. Based on the contents of your deceased father's WILL, partition of the property has to be effected by executing a registered Partition Deed between you and your brother, in the jurisdictional Sub Registrar's Office.

2. After getting the partition effected, submit a copy of the partition deed in the jurisdictional Corporation/Municipal Office, for getting you and your brother's name mutated in the revenue records for your respective shares and then sell your portion of the property to a prospective buyer.

You can still dispose your share to others if you want. Only possession will be an issue

You are at liberty to sell your undivided share In land and top floor 

2) you have already obtained probate of will 

3) will is judicial proof that will is genuine 

4) keep top floor of house locked so that brother does not disturb your possession 

Since you have already got the Will probated, you may have to enforce the Will and take possession of your share in the property as per the recital of  Will. 

If your brother is refusing to vacate your share in the property presently occupied by him, you issue a legal notice demanding him to vacate the same and deliver vacant possession to you. 

Failing to comply or respond to the demands made you may file a suit for partition and separate possession of your share in the property as per the contents of the Will. 

Once you acquire your share in the property you may sell your share of property independently   which cannot be challenged or prevented by your brother for any reason. 

Why court will order you to sell your house? 

You do possess a definite share of the house property. So where is the problem in selling your share of the property? 

Physical condition of your house property is another aspect of  selling your property but there is no legal hardle in selling your property if you get any prospective  buyer. 

You must have a separate entry access to your portion of the house. 

Any one purchase the upper portion of your house will be entitled to possess the half of the UDS. 

Since you are telling your brother have occupied your portion,  it will affect your selling potentiality. Give notice to your brother to vacate your portion. In default file eviction suit or take recourse in other lawful way. 

Other thing it is better to get the mutation record changed in your name. Although after sale purchaser can change it in his favour. 

I think you are getting bit confused about the actual law position. 

Ask if you any further questions regarding this. 

If house is incapable of partition court  can direct sale of the house 

Sale of house is not a regular prayer it will definitely take time. But you can sell your share without possession and go

1. You have already offered your brother to purchase your share of the house which he has refused. Hope it has been recorded in black and white. So, the pre-emption is already over.

2. So, now you can sell of your share of the said property by registering a sale deed to a third party.

1. You can not apply for partition suit for partitioning your deceased father's property since he has executed a will, probate of which has already been taken by you from the Court.

2.So, you shall have to accept the said property  bequeathed to you by your deceased father and deal with it accordingly.

3. Hope you have mutated your share of the said property.

The suit for partition is different to that of the sale of the share of property.

Once you get the property partitioned an you take possession of your property ion all the respects and get the same registered on your name, then you can sell the share of property without taking the consent of your brother or anyone.The partition suit decreed by court will identify your share of property and your will be allotted with separate possession of your share in the property, after that you can independently sell the property

You have two options: 

1. Either sell undivided share in the property by executing "Agreement to sell without transferring possession", place a condition to transfer possession only after partition of the property and make the buyer agree to bare cost of litigation which you may reconcile against sale consideration of property. After execution of this agreement to sell, file a suit for partition and make the purchaser party to your suit. 

2. OR as you have mentioned, you have got probate issued as per the Will of your father; you may execute the Will now and get mutation entries on properties in your name first. Then file suit for partition. During pendency of the suit enter into an agreement to sell for your portion of properties and then get mutation of lis pendens in the property survey numbers stating that the same is alienated to the purchaser during pendency of the partition suit and other than the purchaser, neither your brother, nor you and nor the purchaser himself can sell/alienate the property in your name to any one else until the final disposal of the suit for partition. 

In partition suit the Court won't direct for sale of land at the end of the suit as the nature of the suit is only for determining the share of you and your brother in your father's property. Once that is determined, then prerogative of using or selling it is completely yours.