This article "Copper identified as culprit in Alzheimer's disease" and the study it's about are irrelevant to humans.
This study was done on mice. I hate when people take research on mice as the holy grail for humans. Yes, pretty much every study is done on mice, yes a % of the stuff we find works/causes things on mice ends up being similar in humans however this percentage is SMALL compared to the stuff that very much does not translate to humans. Mice do not eat a lof meat, they have not evolved eating foods with a high copper content, of course introducing something into their system in quantities they don't encounter in nature is going to have an effect.
5g of wheat bran has only .4mg of copper, 5g of corn has .01mg of copper, 5g of potato has .005mg of copper, 5g of acorns have .03mg of copper, 5mg of walnut has .08mg of copper, 5mg of oats have .03mg of copper. These are things wild mice eat.
Now lets look at 5g of veal liver... it has .75mg of copper, 5g of lamb liver has .34mg of copper, 5g of oysters have anywhere from .05mg of copper to .4mg of copper,
Mice eat about 8g of food a day in the wild, they weigh 14.17g to 28.34g and average around 25g. Health non obese people range from 58kg to 81kg+... a mouse might get .64mg of copper a day in the wild. Say a human eats a single wild eastern oyster, they are getting .5mg of copper... I think the RDV for humans is like 1.85mg of copper.
100lb person = 45359.2g and is recommended to take in 1.85mg, a rat in the wild weighs 28.34g and eating a wild diet might get .64mg of copper.
The mice in the study were fed "very low levels of copper, equivalent to what people would consume in a normal diet." meaning the rats were getting 2.89x the higher end of what they might get in the wild. So yeah of course the mice are going to have issues... and as far as relating to humans... it just doesn't, they were getting about 1/15,318th of their body weight in copper, a hundred pound human is recommended 1/24,518,486th their weight in copper.