Trimpey uses that scenario to illustrate his point that until someone says "I don't want to live this way, I want help." then they are not technically addicted, but rather exercising their liberty to use alcohol despite the consequences.
To browbeat her with our opinions of what's best for her and label her as a diseased person may confer upon us a sense of competence or moral goodness, but it is doubtful she will appreciate it or benefit in any way....she is calling the shots, not we, and that the dangers and incoveniences of street life are the cost of her freedom....we may strongly disagree with this woman's judgement that she is really free, and we may believe that what she calls freedom is a prison in which she will needlessly die, but the judgement is hers until she may be declared mentally incompetent. Her prison is better than ours.
Personally, I think he is saying that this woman is choosing her lifestyle as opposed to what everyone else thinks is right for her. One must decide for themselves that it needs to stop. One must have a sincere desire to quit drinking or using, it cannot be externalized. Until this happens, no amount of "treatment" will matter.