Hi heffy, just wanted to bump your post up. I'm sure someone more experienced than me will be along soon, but in the meantime, my own experience of my mam with Alzheimer's and aricept or memantine is that she could only tolerate low doses of aricept as it made her vomit so she was moved onto memantine. Dad feels that her aggression has been worse since the move and her dosage of memantine has been reduced, and other medications have been introduced to try to calm her, such as lorazepam (a sedative, I think), and sertraline and mirtazapine (both anti-depressants). Only the lorazepam seems to help, but the doctor refuses to prescribe anything but a very low dosage of this, so dad has to pick and choose when to give mam her tablet according to what is happening on that day, and when he needs her to be a little calmer.
The aggression is very difficult to deal with, unfortunately. It's my understanding that aricept and memantine can be taken together, if this is suitable, so perhaps this will help your dad. I think it's a bit of 'try it and see'.
Good luck.