You haven't said whether your brother left a will. If he did then all his assets form part of his estate and are to be distributed in accordance with the will. So if he owns the land it is part of his estate.
Whether you sell the land with the business (which I assume your brother owned) depends on whether he did own the land. If he didn't then clearly you cannot sell it with the business unless the owner agrees. If your brother did own both then you need professional advice from a qualified surveyor or agent on what option will maximise the value. There seem to be at least 4:
1. Sell land and business together. That way the buyer might make an unwarranted gain if the land increases further in value.
2. Sell the two separately, but this assumes the business has a value if it has to be moved from the land.
3. Close down the business and then sell the land.
4. Sell the business and rent the land to the buyer until you want to sell it. With this option you must be extremely careful that you do not inadvertently give the buyer of the business any right to remain on the land. (My knowledge of the law here is possibly out of date, but with commercial transactions it used to be the case that a specific legal process had to be gone through to avoid giving security to a tenant.)