Feel very sorry that you are having to face such hard choices.
You are not on your own in feeling like you do and It sounds like you could do with talking to others who have been there too. The Icarus Trust is a charity who support families who have to live and deal with addiction. We offer a range of free services which could include putting you in touch with a trained volunteer called a Family Friend who would talk to you in confidence and try to help. These Family Friends have all experienced dealing with addiction in their own families so would understand what you are facing. You might find talking things through with someone who has been there and knows what support is available, helps you.
Please contact Icarus Trust on help@icarustrust.org or visit our website http://www.icarustrst.org
I really hope that this helps.Good luck!