be careful in what you say about people that are not connected to you i.e. family members etc. You already know that whatever you say will somewhere along the lines probably have an adverse effect on yourself and you could be labelled a trouble maker and action could be taking to make you look like someone to be mocked or avoided, right up to being made to quit your job.
Apart from giving documentation stating the side effects that statins can and do cause and stating that you wish to have put on record the fact that the people in receipt of that information were made aware by yourself of the possible effects and was ignored or deemed not to be of concern in this particular case.
If at a later date the person who you are concerned about has been proven to be damaged by statins and requires legal action against the Doctor who has kept him medicated, then the information is there for his lawyer to use against the Doctor or Doctor's who were made aware of the possible problems and your concerns that this medication may be causing that person.
The fact that you have passed on your concerns should be enough (as long as the nurse also did too), apart from having your concerns put on record, I don't think that there is much else you can do other than going to a Doctor above this one and overruling this decision and that is not very likely to happen as you know.
I am neither a Doctor nor exceptionally clever, but I have worked for a bunch of clowns and I do know what can and does happen in the workplace so please take care. Three of the management where I used to work were known as the 3 witches and often the "W" was replaced with a "B" I am not a violent person but if they were men I would have punched their lights out for the crap I went through, Don't allow yourself to be in a position where someone can make life a living hell.
All the best,