R.K.
Contact Social Services. They should be able to get him into rehab and have it paid for by Medical Assistance.
I recommend that you start going to Al-Anon meetings. Al-Anon is for the families if substance abusers. He can also go to AA or NA meetings (Narcotics Anonymous) find a sponser and get help.
He has to be willing to get help and stop using. If he is not willing to stop you will be on a roller coaster with him. You can also contact his doctor. Where is he getting the medication from?