In a business partnership involving two people as owners, who gets the business if one partner dies without a will?

Assuming you're talking about a partnership in the legal sense, rather than the more general sense, and you have no contrary provision in your partnership agreement, the partnership would be dissolved and your brother's share of its assets would be divided amongst his heirs.  If you're talking more generally about some other form of business structure in which the two of you were co-owners (sole proprietorship, llc, corporation, etc.), and, again, you had no contract dealing with this contingency, the organization would not be dissolved, but your brother's share of the business would, again, go to his heirs. I don't know the exact provisions of Tennessees intestacy law, but generally, the laws of intestacy (when a person dies without a will) provide that a decedent's assets are divided amongst his/her surviving spouse and children.  If there is no surviving spouse or children, surviving parents and/or siblings may inherit.