be of unsound mind
To have impaired or dysfunctional thought, memory, and/or cognitive understanding; unable to think and/or understand for oneself. My poor grandfather has been of unsound mind ever since he suffered that stroke last year.
of unsound mind
Having impaired or dysfunctional thought, memory, and/or cognitive understanding; unable to think and/or understand for oneself. My poor grandfather has been of unsound mind ever since he suffered that stroke last year.