I am posting this personal stuff so other may benefit:
I really can't say one way or the other if the Aricept helped or hindered. In my observation it may have helped keep him lucid for a few months longer and if so I am grateful.
He was pretty decent, slightly "slow" and some hard times talking but still with most of his total faculties until October 2006. He went down hill fast from there and died 15 Apr 2007, only six months later.
On the other hand we, his children, started getting hints of a problem starting in 2001, when we all decided to start having a reunion of sorts every year during my Dad's birthday.
The four children live all around the country and my parents lived in a small village in Northern Michigan, at least until 2001 when my one brother retired and moved only 45 miles from them. Because we were so far apart and did not visit regularly my Mom was able to hide most of his symptoms from us when they visited us. When we all started flying and driving in to them every year we started to notice small problems and it took years to try to help because of my Mom's protective nature and her want to be left alone.
I can not say if giving my Dad Aricept much earlier would have helped or not. Too many variables and not enough empirical evidence to make a good decision.
He was VERY healthy and so I believe he was in such good condition for so long because of that. When he declined it was very fast, unlike others we know. For that I thank God.
But did he take ANY drugs before that?