Lorazepam is a sedative. Has the bf been prescribed them? or is this something he is able to get hold of on the 'Black Market'?
I would urge you to advise your D to try to speak with his doctor if the drug is prescribed. He may be able to help her.
Either way she needs to sit down and talk with the bf to see if he WANTS to sort himself out. If he doesn't and is determined to continue his habit she should seriously consider the future they have.
Good luck,

Womanj x