A very close family member ended up in rehab twice within the space of months a couple of years ago. He was back in the pub the evening of the second day of being released.
I was effectively primary carer. It was absolutely exhausting - and these things have a way plugging into one's own mental health issues. I slightly came apart at the seams as a result, and needed counselling help.
Any acknowledgment, or thanks? Nope. Not a bit. Not even a text message. Calls went unanswered.
A mutual friend ran into my relative in a pub some months later. Said relative said that 'he just wanted to be left to live' his life.
You can't help some. Some don't deserve it.
As someone who went through a very similar experience with a work colleague, I can absolutely sympathise. It is truly exhausting, and thankless thing to go through.
Someone else I worked with at the time said something wise that stuck with me: addicts are selfish people. Either they were, or they become so through the experience.