ANSWER:

It is not permissible to write a will giving something to one of the heirs other than what was prescribed for him in sharia. If he had gifted the shop to them while he was alive and they possessed it from him in his life time, he would be sinful for not being fair with the daughters and giving them equal share.

But if this was not a gift in his lifetime but rather a will to be executed after his death, this will is invalid and they must share his wealth according to sharia law where the boys have nothing to themselves like they are claiming. 

If the Father has named a Shop Just the building to 3 brothers In Written Wasiyah, it is theirs, but what if the shop is of gold and now the sisters are saying that the gold inside should be distributed evenly among all siblings. There is no written proof that the father gave that to the brothers. However, the brothers are saying that in the market they have eye witnesses of father gvng it 2 sons