So, obviously LW should not leave a large lump sum to GD. Indeed, if GD has a family of enablers I'd advise LW not to leave a large lump sum to any of them - decide who inherits, put that money into trusts that are set up to only pay out for specific expenses such as education or the utility bills. This may also be a possibility for GD if LW would like to leave her money but only is worried about how it will be spent.

This is not ideal, none of it is, but it's better to have a reputation as a micromanager and a control freak than to continue to enable a drug addiction after your death.

With that said, I'm not loving how LW allots blame here. GD's partner is not solely responsible for her addiction, I'm sorry, but no. She did not simply start taking drugs to hang out with her boyfriend and then keep taking them for that reason. LW could benefit from a support group for relatives of people with drug addiction. It's entirely possible GD could benefit from medical assistance in quitting drugs - American rehabs are mostly not set up to do this, which is part of why people go in and out of rehab like it's got a damn revolving door.