Hi Claire,
If you think it would be useful, please contact The Icarus Trust as we are a charity that supports people going through what you are, dealing with family member’s addiction.
You could talk to one of our people who are trained and experienced and would listen to you. May be talking to them would help you make sense of things.
You can contact us on help@icarustrust.org or visit the website http://www.icarustrust.org
Good luck.