My Husband Had A Tbi 10 Years Ago (cognitive Disorder/

My husband had a tbi 10 years ago (cognitive disorder/ dementia diagnosed) and made almost a full recovery. For the past 2 years he has been taking medication for a pituitary gland tumor and recently made a full recovery. Here is my concern he has a personality change, aggressive bouts, and is withdrawn. Could he dementia have come back?