What to do if one has had an unsuccessful PhD (because of others' fault)?
There sure are cases, every now and then, of researchers (professors or other) abusing students in various ways. As everyone, I have heard stories, and I know at least a couple of people who have been put in dramatic situations during their PhD. However bad the behavior of the advisor is, it turns out that there are multiple venues one can try, during the PhD, when the alarm flag is raised. These depend on the institution and type of employment, but they include:


Going to see the PhD program director, explaining your situation (diplomatically) and asking for advice (read: help).
Finding a friendly researcher/professor in your department, and ask him for advice (and possibly help) with your issue. They know the people and local “politics”, and might have efficient advice.
Your employer's HR department
Going to your professor's hierarchy (department chair, dean, …). As a last recourse, file a formal complaint.
Get someone to speak for you: a union representative, a member of the local “PhD association”, etc. That can help if you are worried about the fallout of intervening directly.
Changing your plans to work on a more “independent” research. In your example, your friend was denied access to a given experiment. If the experiment had broken down beyond repair, he sure could reörient his research, so the same thing could be done in the case at hand (I'm not saying it's easy).
Walking out (or, as JeffE would surely say: don't walk, run!)


Regarding legal action: I don't think this avenue can lead anywhere, unless there is factual evidence of gross misconduct or unethical activity. The burden of proof relies on your friend, and I think it will actually be harder to complain after the fact if he did not raise his concerns formally during his PhD.