Cocaine works on the nervous system similar to MS ------ and the only recreational users are those that at some time run out or get cut off somehow. Its a nasty drug.....and not friendly to the body. At the very least talk with the brother. I would seriously consider the Doc also. How would you feel if he misdiagnosed and subsequently medicated improperly because of lack of information?
i'm sorry i don't know... that may be a question only a doctor can answer.
i can only say if it were me, i might tell the doctor anyway. to help your brother. he may be mad for the time being, but hopefully eventually he will know you did this simply because you love him.
i think it's always best to get these things out in the open - with your brother, even with the doc. it's not talking about them that hurts everyone.. especially you.
it's only my opinion. i'm sorry i could not help better... :-/
i wish you alot of love and luck with this...
warmly,
mary