Tenn. Code Ann. § 45-3-510: Incompetency of a joint tenant

(a) The adjudication of incompetency of any one (1) or more of the joint tenants shall not operate to sever or terminate the joint tenancy ownership of all or any part of the account, and the account may be withdrawn or pledged by any one (1) or more of the joint owners in the same manner as though the adjudication of incompetency had not been made, except that any withdrawal or pledge on behalf of the incompetent joint owner shall be by guardian or conservator.

(b) Payment of any or all of the moneys in the account shall discharge the association from liability with respect to the moneys so paid.