Does it matter what the causes are? He's sick, you can't fix, save or cure him.
I'm very sure he's right that 'it's not easy' to be an addict. I'm equally sure it's not easy to love one either.
Also, IME most/all addicts have a sob story or four that they wheel out whenever it might be useful to them.
Are you doing anything for your own recovery? That's the only one you can control.