Martha gave you lost of good advice and Joel as well. The effectiveness of the medications depends on the person. It is worth trying. Keep a lot of behavior and possible side effects. That will help you determine what is going on before and after the medication is given. I have not seen any improvement since Mom started the Namenda and Aricept. Actually there has been a rather constant rapid decline. I actually think the namenda is contributing to her aggitation. But it is hard to tell. No medication can reverse the effects of this disease. It only promises a possible slowing of the effects.
Martha is right about the POA and medical documentation. Someone elses names should also be on all accounts. These are necessary for someone to handle his personal affairs and medical treatment when he can not do it.
Is he living alone? You will need to keep a careful watch on him. There will come a time, sooner rather than later, when he will not be able to live alone. simple task like fixing supper will become impossible or dangerous. Money seems to be a point where they slip quickly. They become a prime target for scam artist. They also forget to pay bills or pay them repeatedly.
I hate that you have to deal with this situation but you have found the right place. We have all been where you are. We do understand. This is a wonderful place to hear the experiences of others, get advice, find empathetic, sympathetic ears, to vent when necessary, and find support. So come back often
Love, deb