given that she's obviously smoking this much because she can't get 
high any more, she's probably actually at risk of moving to something 
harder.
i've seen studies arguing both ways, and 
they're probably both right, depending on the context. i can understand 
how marijuana could help a heroin addict - although i might suggest 
methadone, instead. less harmful. on the other hand, when your tolerance
 to marijuana is as absurd as this woman's is, and the delivery method 
is giving you pneumonia, it's easy to understand the appeal of something
 stronger, too.
it probably depends on what stage the 
addict is in. an opiate addict that wants to get better but is 
physically addicted could use pot as a crutch, even if they relapse in 
the long run; a desperate pothead that just isn't getting high anymore 
might look at opiates as the only way to get what they're after. and, i 
might have thought that was obscure a few months ago, but i never 
thought i'd meet somebody that smokes as much as she does, either.
she's obviously just not getting high.