It depends on what's being studied. There are mice studies on diet which obviously don't carry over to human beings since we don't have similar digestive systems. It may be true (arguable) that all research data is of some benefit, but don't expect people to be as excited about mouse research as human research.

How do they get the alzheimers mice? Article doesn't say. Usually in studies they take healthy mice and induce the condition artificially. That can be a confounding factor since the condition isn't induced in the specimens we care about (human beings). Is it even the same condition?

It doesn't matter how they give mice alzheimers, or any other condition. That's just part of controlling variables to test for one thing. It also doesn't matter that they were fed processed food rather than having to find things in the wild, unless the effect of diet was the specific thing they were examining.