It`s important to keep in mind that even though there has been a change in personality, the personality itself has remained. It`s necessary to organize a space and a favorable atmosphere for the patient (e.g., to arrange the room with favorite furniture, old photos, etc). It`s necessary to keep in touch with the person and integrate him or her into society. Also, it is worth taking his needs seriously and talking about them. I know about a service https://www.thekey.com/learning-center/alzheimers-and-dementia-caregiving/how-to-have-more-good-days-with-dementia that cares for people with this disease. Such services help if you can't be around all the time. Feel free to accept outside help, it's fine.