Why do my 84 and 86-year-old parents with dementia lay in bed so much?

I know where you are coming from. My 90 year old father was a very hard working man a drywaller and farmer before retirement and dementia. Now all he wants to do is find his bed not always to sleep but to just to lie down. His often asked question is Do I have a bed and I thought I had a bed. It takes a lot everyday to keep his focus on other things and I try to let him lie down everyday for 2 to 3 hours after lunch. This seems to help but he will always ask about his bed. Even when passing his room on the way to the bathroom he will notice his bed and try to go in therefore I will keep his door closed most of the time out of sight out of mind -sometimes. I know he worked hard to raise 7 children and he deserves his rest but at this time lying in bed too much is the worst thing for his aging body. He would stay in bed forever if I didn't get him up forget eating and only get up for the bathroom. I have him sit in his recliner with legs up during the day with a gel cushion in the seat and allow him to take a nap for 2 to 3 hours after lunch this seems to help allowing him his bed time every day. Caring4Daddy 9/25/12