Elder male dementia patient sleeping 15+ hrs/day. what are causes? losing weight due to missing meals though appetite remains very good generally.

In San Diego we: have APS--Adult Protective Services. It's the adult verion of CPS (Child), and is designed to assess elders who may need assistance with hygiene, food, shelter, money management, etc. APS usually has a psychiatric component to help assess mental capacity and any needs for assistance (caregivers,medical, social programs, placement in facilities--all as needed).