I see stopping a working statin as a foolish choice, as backed up be the evidence:
Stopping cholesterol-lowering drugs could be deadly | Reuters

Now having said that, if someone looks at the evidence, the odds, and the consequences, and decides to do something I see as foolish, I can't stop that person from doing something that may end up killing them, or leaving them an invalid, or causing intense pain for them and grief for their family and friends. But I would certainly urge such a person to reconsider that decision.